Glossary of Astrology Terms
Ninety-three terms, grouped and defined once each, with a column saying where the term turns up in Zodiux's own tools — including the thirty-odd where the answer is that we do not compute it.
Astrology has a large vocabulary and no agreed dictionary, which is how one word ends up meaning three things across two websites. This page defines the terms you actually meet on a chart, grouped by what they belong to, one or two sentences each. The third column is the part other glossaries do not have: where the term turns up in Zodiux's own tools — and, for thirty-odd of them, a flat statement that we do not calculate it. A glossary that lists only what a site can do is a sales sheet.
How to read these tables
Definitions are for Western tropical astrology, the tradition Zodiux works in. Where a term means something different in Vedic or Chinese astrology, that is a different system with its own literature, not a variant spelling, and the last definition table says which is which.
Where Zodiux takes a specific position — tropical rather than sidereal, no house cusps in the free chart, three equal 10° decans, five fixed orbs — the row says so, with the number, rather than leaving you to infer it. Where a term describes something we deliberately do not calculate, the row says that instead. The reasoning behind each refusal lives in how Zodiux computes your chart and what we do not claim; this page is the index to them, not a second copy.
Nothing here predicts anything. These are definitions of a symbolic tradition, written for reflection and entertainment.
The chart itself
The vocabulary of the object: what a chart is, what quantity it plots, and what the picture is called.
| Term | What it means | Where it turns up on Zodiux |
|---|---|---|
| Birth chart (natal chart) | A map of where the Sun, Moon and planets stood along the zodiac at one moment, seen from one place on Earth. A snapshot of positions before it is anything else. | The free birth chart calculator draws one, entirely in your browser. What a birth chart is is the long version. |
| Ephemeris | A table or algorithm giving a body's position for any date. The raw input astrology shares with navigation and astronomy. | Astronomy Engine, an open-source implementation of the VSOP87 and NOVAS algorithms. The same library runs in your browser and in the build that generated this page, so the two cannot drift apart — data sources fingerprints both copies. |
| Ecliptic | The plane of Earth's orbit projected onto the sky, which is the Sun's apparent yearly path. Every zodiac measurement is taken along it. | Implicit in every position on the site. Nothing here is measured against the celestial equator. |
| Ecliptic longitude | One number from 0° to 360° giving a body's position along the ecliptic, counted from 0° Aries. Divide by 30 and you have the sign. | The only quantity Zodiux computes. Sign, degree, aspect and retrograde state are all arithmetic performed on it — the pipeline, step by step. |
| Geocentric | Measured from the centre of the Earth, rather than from the Sun (heliocentric) or from your exact spot on the surface (topocentric). | What Zodiux reports: geocentric apparent longitude. |
| Apparent position | Where a body appears from here and now, rather than where it is: corrected for the time its light took to arrive and for the Earth's own motion. | The ephemeris is asked for the aberration-corrected vector on every call — chart, sky strip and retrograde tracker alike. There is no uncorrected code path. |
| Degree and arcminute | A sign is 30 degrees wide; one degree is 60 arcminutes. Placements are conventionally written sign-plus-degree, as in 14° Taurus. | The chart prints the whole degree and floors it: 21.98° of Cancer displays as 21°, not 22°. Arcminutes are never shown, though the figure underneath is far finer. |
| Chart wheel | The circular drawing: zodiac ring outside, bodies plotted by longitude inside, aspect lines drawn across the middle. | Zodiux draws three rings, twelve sign divisions, ten bodies and the aspect web. Given a birth time the wheel is rotated so the Ascendant sits at nine o'clock; with no birth time, 0° Aries takes that spot instead. |
| Big three | Sun sign, Moon sign and rising sign taken together — the three placements people are usually asked for. | Three cards at the top of every chart, and the only three placements the free chart writes an interpretation for. What the big three is. |
Signs, elements and modalities
A sign is a stretch of longitude, not a constellation. The constellations along the ecliptic are wildly unequal — the Sun crosses about 7° of Scorpius and about 44° of Virgo — and there are thirteen of them, because the ecliptic also passes through Ophiuchus. Their boundaries have not overlapped since the IAU fixed them in 1930, but not one of them lines up with a sign boundary either; the twelve signs are exactly 30° each by definition. Confusing the two is the origin of the recurring "your sign has changed" news story.
The element and modality rows carry numbers because those two properties are not decorative here: they are the entire input to the score on a static compatibility page. Each dimension of that score is 58% element, 42% modality, plus a modifier for the angle between the signs. Each element happens to top exactly one dimension of the element table, which is why the four rows below read differently.
| Term | What it means | Where it turns up on Zodiux |
|---|---|---|
| Sign | One of twelve equal 30° divisions of the zodiac. Not a constellation — the ecliptic constellations are thirteen, of wildly unequal width, and none of their edges coincides with a sign edge. | Every position on the site is reported as sign plus degree, taken as the longitude divided by 30, whole part only. |
| Tropical zodiac | Signs measured from the March equinox point, which is defined as 0° Aries. Western astrology's convention for roughly two thousand years. | What Zodiux uses, everywhere, with no option to switch. |
| Sun sign | The sign the Sun occupied on your birth date — the one a newspaper column means by "your sign". | What a sun sign is. Date ranges shift by up to a day between years, so a birthday at the edge needs the actual chart, not a date table. |
| Element (triplicity) | Fire, Earth, Air or Water. Every sign has one, and signs four apart share it. | The elements. Derived as the sign index modulo 4, which is why Aries, Leo and Sagittarius are all Fire. Supplies 58% of every dimension of a static pair score. |
| Fire signs | Aries, Leo, Sagittarius. Traditionally read as initiative and heat — energy spent rather than stored. | Tops the chemistry column of the pair-page element table, at 90. |
| Earth signs | Taurus, Virgo, Capricorn. Traditionally read as material, patient, concerned with what lasts. | Tops staying power, at 92. |
| Air signs | Gemini, Libra, Aquarius. Traditionally read as language, comparison and a step back from the feeling. | Tops communication, at 92. |
| Water signs | Cancer, Scorpio, Pisces. Traditionally read as feeling-first, retentive, permeable. | Tops emotional sync, at 92. Pairs as "compatible" with Earth, on the same parity rule that pairs Fire with Air. |
| Modality (quadruplicity) | Cardinal, Fixed or Mutable: how a sign moves rather than what it is made of. Signs three apart share it. | The modalities. Derived as the sign index modulo 3, and worth the other 42% of a pair score. |
| Cardinal | Aries, Cancer, Libra, Capricorn — the signs that open each season. Read as starting. | Highest of the three modalities on chemistry, at 80. |
| Fixed | Taurus, Leo, Scorpio, Aquarius — mid-season. Read as holding. | Tops both staying power (92) and emotional sync (78). |
| Mutable | Gemini, Virgo, Sagittarius, Pisces — the end of a season. Read as adapting. | Tops communication (88) and comes last on staying power (64). |
| Cusp | Strictly, the boundary between two signs. A body sits on one side of it or the other — there is no third sign in between. | What a cusp is. Zodiux never places a body "on the cusp": 29.99° of Cancer is Cancer, and the calculator returns the sign the degree falls in. |
| Decan (face) | A third of a sign — 0°–9°59′, 10°–19°59′, 20°–29°59′ — each given a sub-ruler on top of the sign's own. | Three equal 10° decans, one page each. The 36 birthday pages name the Chaldean face and the triplicity decanate, because the two schemes agree on only 9 of the 36. What a decan is. |
Planets and luminaries
The ten bodies Western astrology reads, plus the groupings it sorts them into. All ten are computed and printed by sign, degree and retrograde state in the free chart; the planets in astrology is the guide to what each is read for.
The speeds in the middle column matter more than they look. A body that takes fourteen years to cross a sign puts everyone in your school year in the same sign, which is why an outer planet read at sign level describes a cohort rather than a person.
| Term | What it means | Where it turns up on Zodiux |
|---|---|---|
| Luminaries | The Sun and Moon. Not planets, and traditionally read as the two lights the rest of the chart is arranged around. | The two bodies exempted from the retrograde test in the code — neither can ever be flagged ℞, because neither ever appears to reverse. |
| Personal planets | Sun, Moon, Mercury, Venus, Mars. Fast enough that two people born the same week can differ. | All five are among the seven bodies the compatibility tool compares, and the three heaviest cross-aspect weights in that tool are pairs of them: Sun–Moon, Venus–Mars, Moon–Moon. |
| Outer (generational) planets | Uranus, Neptune, Pluto. Slow enough to share a sign with everyone born within years of you. | Computed and printed in your placements list like any other body. The free chart writes an interpretation for the Sun, Moon and rising sign only — the outer three get a position and no paragraph. |
| Sun | Traditionally identity and vitality — the thing a life is organised around. Averages 0.9856° a day. | Your sun sign, and the "season" reading in the today's-sky strip that heads the home page, the twelve sign pages and every learn article — 45 pages, not the decan pages, which projects the next ingress forward at exactly that rate. The sky page itself prints live positions rather than that strip. |
| Moon | Traditionally needs and mood — what settles you. The fastest body in the chart, covering up to about 15° in a day and a whole sign in about two and a quarter — a twelfth of the 27.32-day sidereal month. | Moon sign calculator — birth date, time and time zone, no birthplace needed. Leave the time blank on a day the Moon changed sign and it names both possibilities rather than picking one. |
| Mercury | Traditionally thinking, speech and exchange. Never more than about 28° from the Sun, so it sits in your Sun's sign or one next to it. | Is Mercury retrograde right now computes it live, from the same ephemeris as the chart. |
| Venus | Traditionally attraction, taste and what you value. Never more than about 47° from the Sun. | One of the seven bodies the compatibility tool compares across two charts. |
| Mars | Traditionally drive and anger — how someone goes after a thing. Averages about eight weeks per sign, far longer when a retrograde carries it back and forth. | Same seven. Venus–Mars is the second-heaviest pair in that tool's weighting. |
| Jupiter | Traditionally expansion, belief and appetite. Roughly a year per sign. | Same seven; also one of the ten bodies in the live sky orrery. |
| Saturn | Traditionally limit, structure and the cost of things. Roughly two and a half years per sign. | Same seven. Its return to your birth degree is the Saturn return, which Zodiux describes but does not date for you. |
| Uranus | Traditionally disruption and abrupt change. About seven years per sign. | Computed in the chart and in the live sky. |
| Neptune | Traditionally dissolution, imagination and blur. About fourteen years per sign. | Same. A sign-level Neptune reading describes a fourteen-year cohort, not a person. |
| Pluto | Traditionally compulsion, power and what will not stay buried. From about eleven years in Scorpio to about thirty-two in Taurus, because its orbit is so eccentric. Reclassified a dwarf planet in 2006; astrology kept it. | Same — and the least personal placement in the chart, for the reason in the middle column. |
Angles, nodes and calculated points
These are not bodies. Each is a point derived from geometry — the horizon, the meridian, an orbit crossing — and most of them need an exact birth time and place, which is why they vanish when the time is unknown.
| Term | What it means | Where it turns up on Zodiux |
|---|---|---|
| Angles | The four points where the chart's local frame meets the zodiac: Ascendant, Descendant, Midheaven and Imum Coeli. All four depend on the birth time and place, not just the date. | Only the Ascendant is computed. The other three appear nowhere in the chart code. |
| Ascendant (rising sign) | The zodiac degree climbing over the eastern horizon at the birth moment, derived from local sidereal time at the birth longitude. Moves about a degree every four minutes. | Computed and printed whenever a birth time and city are given. With no birth time it is omitted rather than guessed — it changes sign every two hours on average, and the average hides the problem: at London's latitude the Ascendant crosses Aries in under an hour and Leo in nearly three. What a rising sign is. |
| Descendant | The point exactly opposite the Ascendant, setting in the west. Read for partnership. | Not printed. It is always your rising degree plus 180°, so nothing is lost by leaving it out. |
| Midheaven (MC) | Where the ecliptic crosses the meridian above you: the highest point of the chart, read for vocation and public role. Its opposite, the lowest point, is the Imum Coeli or IC. | Not computed. What the midheaven is explains what that costs you and why it is deliberate. |
| Lunar nodes (North and South) | The two points where the Moon's orbit crosses the ecliptic. Eclipses happen when a new or full Moon lands near one. They travel backwards through the zodiac, a full circuit in about 18.6 years. | The lunar nodes. Not among the ten bodies the free chart computes. |
| Chiron | A small body orbiting between Saturn and Uranus, discovered in 1977 and read in modern astrology as a site of injury and repair. | Not computed. |
| Part of Fortune | An Arabic part: a point calculated from the Ascendant, Sun and Moon rather than an object in the sky. | Not computed — and undefined without a birth time anyway, since it needs the Ascendant. |
Houses
Houses divide the chart by the Earth's daily rotation rather than by the zodiac. Signs are read as how; houses claim to say where in life. They are also the single largest disagreement in astrology: pick a different house system and planets change houses, sometimes several at once.
Zodiux's free chart draws no house cusps at all, and computes no aspects to the angles either. It takes no position on Placidus versus Whole Sign versus Koch, because that choice changes the answer and we would rather make the refusal explicit than pick one silently. What houses are covers the systems properly.
| Term | What it means | Where it turns up on Zodiux |
|---|---|---|
| House | One of twelve divisions of the chart based on the Earth's rotation during the day of birth. Numbered anticlockwise from the Ascendant. | Discussed in the guides, drawn nowhere in the free chart. |
| House cusp | The boundary degree where one house begins. Which degree that is depends entirely on the system you chose. | Not computed — the deliberate refusal stated in the methodology. |
| Whole Sign houses | The oldest surviving system: the sign containing the Ascendant is the entire first house, the next sign the second, and so on. No arithmetic, no distortion at high latitude. | Whole sign houses explains it. Zodiux still does not pick it for you. |
| Solar houses | The same whole-sign counting, but started from the Sun's sign instead of the Ascendant — the standard workaround for a horoscope written without a birth time. | The one place house language appears in a Zodiux tool: the daily line on each sign page counts whole signs from your sun sign to today's Moon. It is not a birth-chart house system and does not pretend to be. |
| Placidus | The most widely used modern system. It divides the time a degree takes to rise, so house sizes vary — and it breaks down above roughly 66° latitude, where some degrees never rise at all. | Named, not used. |
| Koch | A twentieth-century time-based system. Like Placidus, it fails near the poles. | Named, not used. |
| Equal House | Twelve 30° houses counted from the exact Ascendant degree, so the first cusp is the Ascendant itself. | Named, not used. |
| Angular, succedent, cadent | The three-way grouping of houses by position: angular (1, 4, 7, 10) begin at the angles and are read loudest; succedent (2, 5, 8, 11) follow them; cadent (3, 6, 9, 12) precede them and are read as the most changeable. | Vocabulary only. |
Aspects, orbs and chart patterns
An aspect is the angular distance between two bodies along the ecliptic. It is one subtraction — take one longitude from the other, and if the result exceeds 180° subtract it from 360°. How close that number lands to one of a short list of exact angles is the whole mechanic. Aspects explained is the full guide.
The orbs below are the ones Zodiux's own chart uses, and they are published because they are a choice, not a measurement. Astrologers disagree about orbs by several degrees, and a wider orb finds more aspects — which is exactly why a site that will not state its orbs has not given you enough to check its output.
| Term | What it means | Where it turns up on Zodiux |
|---|---|---|
| Aspect | The angular distance between two bodies, measured along the ecliptic. Geometry first; interpretation afterwards. | The free chart tests all 45 pairs of the ten bodies and prints the eight tightest, sorted by distance from exact. |
| Orb | How far from exact an aspect may fall and still be counted. A convention, not a measurement. An aspect with an orb near zero is called exact, or partile. | Fixed: 7° for conjunction, trine and opposition, 6° for square, 5° for sextile — the same five windows in the birth chart and in the synastry tool. In the chart nothing widens them for the Sun or narrows them for Pluto; the synastry tool never reads Pluto at all, because it works from seven bodies rather than ten. |
| Applying / separating | An aspect is applying while the faster body is still closing on exact, and separating once it has passed. | Not distinguished — and the orb figure is not printed either. Zodiux uses the orb to rank the list and cut it at eight; what you see is the aspect's name, not its tightness. |
| Hard and soft (easy) aspects | The conventional split: squares and oppositions are read as friction, conjunctions, sextiles and trines as flow. A convention about interpretation, not about geometry. | The only weighting the chart applies. Squares and oppositions are flagged hard in the code and drawn in a different colour on the wheel from the other three. |
| Conjunction (0°) | Two bodies at the same longitude, read as acting as one unit. The flavour comes entirely from which two. | What a conjunction is. Widest orb on the list, at 7°. |
| Sextile (60°) | The circle divided by six. Read as an opportunity that has to be picked up rather than one that arrives. | In the chart's aspect list with a 5° orb — the tightest window of the five, so the aspect the chart is least likely to report. |
| Square (90°) | Divided by four. Friction between two bodies working at the same tempo toward incompatible ends. | What a square is. Orb 6°, and flagged hard. |
| Trine (120°) | Divided by three, and always between signs of the same element — unless it crosses a sign boundary. Read as ease, which is not the same as good. | What a trine is. Orb 7°. |
| Opposition (180°) | Divided by two. Read as confrontation, and as visibility — you can see the far end of a see-saw. | Orb 7°, flagged hard. Its window is one-sided: separation cannot exceed 180°, so it accepts 173° to 180°. |
| Minor aspects | Semisextile (30°), semisquare (45°), quintile (72°), sesquiquadrate (135°), quincunx (150°) and others, read faintly and with orbs of a degree or two. | The chart ignores all of them. The 78 static pair pages do use the 30° and 150° harmonics, because sign distance forces all seven — the model. |
| Out-of-sign (dissociate) aspect | An aspect exact by degree that crosses a sign boundary, so the signs it connects are not the ones the aspect is supposed to link. | Found correctly, because Zodiux subtracts longitudes rather than counting signs. 29° Taurus (59°) and 1° Virgo (151°) are 92° apart — 2° off an exact square, well inside the 6° orb — even though the two signs are four apart, which is trine distance. |
| Stellium | Three or more bodies bunched together in one sign, or in one house where houses are used. | What a stellium is. Not labelled by the chart, but visible as a cluster on the wheel. |
| T-square | Two bodies in opposition, both square a third. A grand cross adds a fourth body opposite the apex. | Not labelled as a pattern. The component aspects appear individually, and only if each is separately inside orb. |
| Grand trine | Three bodies roughly 120° apart, usually all in one element. | Not labelled either — the three trines appear as three ordinary rows. |
Motion and timing
Everything above is a still frame. This group is the vocabulary for what the sky does next, and for the handful of moments astrology treats as significant.
| Term | What it means | Where it turns up on Zodiux |
|---|---|---|
| Retrograde | The apparent backwards motion of a planet against the zodiac, caused by Earth overtaking it or being overtaken. Nothing physically reverses; forward travel, the normal state, is called direct motion. | What retrograde means. Flagged by comparing a body's longitude with its longitude 24 hours earlier — a day-resolution test, so a station day can fall either way. The Sun and Moon are never flagged. |
| Station | The moment a planet's apparent motion pauses before flipping: stationary retrograde, then weeks later stationary direct. | The Mercury retrograde tracker finds them by sampling one day at a time from 220 days behind you to 430 days ahead, then pairing each flip into a period. Computed live in your browser; no dates are stored anywhere. |
| Shadow period | The stretch before and after a retrograde in which the planet covers the same degrees it will cross three times. A modern popular addition, not a classical one. | Not reported. The tracker gives the retrograde period itself and nothing around it. |
| Ingress | A body crossing from one sign into the next. The Sun's ingress into Aries is the March equinox, which is where the tropical zodiac starts counting. | The strip's Sun row — a season name, then a "through <date>" line — names the next solar ingress. It is projected forward at 0.98565° a day rather than solved for exactly, which on a typical crossing lands within a couple of hours of the true instant. |
| Lunation | A new or full Moon. One new Moon to the next averages 29.53 days. | Vocabulary. The current phase sits in the sky strip at the top of every learn article and sign page. |
| Moon phase | Named from the Moon's angular distance from the Sun: 0° at new, 180° at full. | Two schemes ship, and they can disagree. The sky strip gives the four exact phases a 22.5° window each and the four in-between ones 67.5°; the daily line on a sign page splits the cycle into eight equal 45° buckets instead. Between 11.25° and 22.5° past new the sign page still says New Moon while the strip has already moved to waxing crescent, and they part company again between 337.5° and 348.75°, where the sign page says New Moon and the strip says waning crescent. |
| Void-of-course Moon | The stretch after the Moon's last major aspect in a sign and before it enters the next. Traditionally read as a poor window for starting things. | Void-of-course explained. No Zodiux tool computes it — it needs the Moon's aspects to every other body across a whole sign, which nothing here calculates. |
| Eclipse | A lunation close enough to a lunar node for Sun, Earth and Moon to line up: solar at a new Moon, lunar at a full one. | Vocabulary only. Zodiux publishes no eclipse table, and since it computes no nodes it could not build one from what it has. |
| Transit | A body's position now, and the angle it makes to a placement in your birth chart. The everyday raw material of astrological timing. | The sky right now is today's transiting positions for all ten bodies. No free tool compares them against your birth chart; the sign pages compare today's Moon against your sun sign only. |
| Return | A body arriving back at the exact longitude it held at your birth. The solar return is your birthday; the Saturn return lands near 29 and again near 59. | What a Saturn return is. No return chart is cast by any free tool. |
Techniques: charts made from other charts
Most named astrological techniques are a rule for building a second chart, or for comparing two. The rule is usually simple, and always arbitrary in the sense that it is a convention rather than a measurement — worth remembering whenever a technique is described as revealing something.
| Term | What it means | Where it turns up on Zodiux |
|---|---|---|
| Natal astrology | Reading the birth chart itself, rather than a chart derived from it. | Everything the free chart does. |
| Synastry | Comparing two birth charts by measuring the aspects between one person's bodies and the other's. | What synastry is. The compatibility tool does this for real: two full charts, seven bodies each — Sun through Saturn — tested across all 49 combinations at the same five orbs the birth chart uses. |
| Sun-sign compatibility | The much cruder version: score two signs against each other from element, modality and the angle between them. | What the 78 static pair pages do, and they say so on themselves. The scoring model is published line by line at compatibility scores. |
| Composite chart | A third chart built from the midpoints between two people's placements, read as the relationship rather than either person. | Not computed. |
| Progressions | A symbolic technique. Secondary progressions advance the chart one day per year of life, so your thirtieth day of life describes your thirtieth year. | Not computed. |
| Solar return chart | A chart cast for the moment the Sun returns to its natal degree, read for the year ahead. | Not computed. |
| Horary | Casting a chart for the moment a question is asked and answering from that chart alone. A distinct tradition with its own rulebook. | Not offered. |
| Rectification | Working backwards from known life events to estimate an unknown birth time. Contested, and unavoidably circular. | Not attempted. With no birth time the rest of the chart is computed for local noon and the rising card reads "add birth time" where a sign would go. |
Systems, traditions and the astronomy underneath
The last definition group is the one that settles arguments. Most "astrology got my sign wrong" disputes are really a tropical-versus-sidereal disagreement, and most "astrologers cannot agree" complaints are two traditions being quoted as though they were one.
| Term | What it means | Where it turns up on Zodiux |
|---|---|---|
| Sidereal zodiac | Signs measured against the actual constellations rather than the equinox point. Currently about 24° behind the tropical zodiac, so most people's sun sign differs by one. | Not used. A Vedic chart disagreeing with a Zodiux chart is expected, not an error in either. |
| Ayanamsa | The number of degrees separating the tropical and sidereal zodiacs. Several competing values exist; the Lahiri ayanamsa is the most widely used. | Not applied — there is no sidereal option here to apply it to. |
| Precession of the equinoxes | The slow wobble of Earth's axis that moves the equinox point about 1° every 72 years, and the reason the two zodiacs drift apart. A full circuit takes roughly 25,800 years. | The reason the tropical choice has to be stated rather than assumed. |
| Obliquity of the ecliptic | The tilt between Earth's equator and its orbital plane: about 23.44°, decreasing by roughly 0.013° per century. | Held fixed at 23.4367° inside the rising-sign calculation rather than recomputed per birth date. That is the mean value for around 2020; by the date at the foot of this page it is 23.4358°, a gap of about three arcseconds. It is the one simplification Zodiux names, and the cost is measured rather than asserted. |
| Local sidereal time | Time measured by the stars rather than the Sun, at your longitude. It is what turns a birth time and place into an Ascendant. | Computed for every chart that has a birth time, and the only place your birth longitude enters the arithmetic at all. |
| Hellenistic astrology | The Greco-Roman system, roughly 100 BCE to 600 CE, from which whole sign houses, sect and the classical dignities descend. Recovered and revived from the 1990s onward. | The source of whole sign houses and of both decan-ruler schemes named on the birthday pages. |
| Modern (psychological) astrology | The twentieth-century turn away from prediction toward character and meaning. Most of the vocabulary popular astrology uses today comes from here. | The register the interpretations are written in — description, not prediction. |
| Vedic astrology (Jyotish) | The Indian tradition: sidereal zodiac, its own house and timing systems, its own literature. A separate system, not a dialect. | Not covered. Zodiux does not translate between the two. |
| Sun-sign astrology | The newspaper-column format: twelve readings from a birth date alone. Popularised in Britain in 1930 and dominant ever since. | The shape of the sign pages and the static pair pages — both of which state what a birth date alone leaves out. |
| Essential dignity | Whether a planet sits in a sign it rules (domicile), is exalted in, or is weakened in (detriment, fall). The traditional way of calling a placement strong or awkward. | Sign rulers appear on the sign pages and in the decan table. Dignity itself is never scored, and nothing here calls a placement good or bad. |
The symbols on a Zodiux chart
Glyphs are the part of a chart that looks like a secret and is not. There are twenty-seven, plus one marker and one three-letter label, and this is the whole key. The chart appends a text-presentation selector to the twelve sign glyphs and the ten planet glyphs, so they paint as gold line drawings rather than the colour emoji squircles some platforms would otherwise substitute. The five aspect glyphs and ℞ are printed bare — they have no emoji form to suppress. The written report, the sign pages and the sky strip force the same twenty-two.
A placement row prints as glyph, name, in, sign glyph, sign name, with the degree in its own column: ☿ Mercury in ♌ Leo and 14° means Mercury's ecliptic longitude was somewhere in 134.00°–134.99°, since 134.72 divided by 30 gives sign index 4 (Leo) with 14.72° left over, floored to 14. An aspect row prints the aspect's name, then both bodies with the aspect glyph between them: ☿ Mercury □ ♀ Venus.
| Group | Glyphs, in order | Note |
|---|---|---|
| The twelve signs | ♈ Aries · ♉ Taurus · ♊ Gemini · ♋ Cancer · ♌ Leo · ♍ Virgo · ♎ Libra · ♏ Scorpio · ♐ Sagittarius · ♑ Capricorn · ♒ Aquarius · ♓ Pisces | Zodiac order, which is also the index order the code counts in: Aries is 0, Pisces is 11. |
| The ten bodies | ☉ Sun · ☽ Moon · ☿ Mercury · ♀ Venus · ♂ Mars · ♃ Jupiter · ♄ Saturn · ♅ Uranus · ♆ Neptune · ♇ Pluto | Sun outward. The sky orrery draws the Moon as ☾ and the chart as ☽ — two Unicode forms of the same body, not two different things. |
| The five aspects | ☌ conjunction · ✶ sextile · □ square · △ trine · ☍ opposition | The complete set. No sixth glyph exists in the chart, because no sixth aspect is tested. |
| Retrograde | ℞ | Printed beside a placement whose longitude was decreasing over the preceding 24 hours. Never appears on the Sun or Moon. |
| Ascendant | ASC | A word rather than a glyph: a gold tick on the rim of the wheel, labelled, at your rising degree. Absent when no birth time was given. |
That is the entire visual vocabulary, and what a birth chart is walks the same key in reading order, with the marks placed on an actual wheel. If you see a glyph on another site that is not in this table — ⚷ for Chiron, ☊ for the North Node, ⊗ for the Part of Fortune, ⚸ for Black Moon Lilith — it belongs to a point Zodiux does not calculate, and the angles-and-points table above says why.
One word, two meanings
These are the pairs that cause the most confusion, usually because the same word survived into two systems that mean different things by it. The third column is which one Zodiux means when it uses the word without qualifying it.
| The word | The two things it can mean | Which one Zodiux means |
|---|---|---|
| Cusp | The boundary between two signs, or the boundary degree where a house begins. | The sign boundary. Zodiux computes no house cusps, so the second sense never arises in a Zodiux tool — what a cusp is sets the two side by side. |
| House | A twelve-fold division of a birth chart by daily rotation, or — in Whole Sign and solar-house usage — simply a sign counted from a starting point. | Neither, in the free chart. The only house-shaped thing on the site is the solar-house count on a sign page's daily line. |
| Ruler | The planet that rules a sign, the planet ruling your rising sign (chart ruler), or a decan's sub-ruler. | All three appear, always labelled. The sign pages give sign rulers, the birthday pages give both decan schemes, and the free chart does not name your chart ruler at all. |
| Return | A body coming back to its natal degree (the event), or a chart cast for that moment (the technique). | The event only. Zodiux describes the Saturn return and casts no return charts. |
| Sign | A 30° division of the tropical zodiac, or the constellation of the same name. | The 30° division, always. The constellation of the same name is a different width and in a different place. |
| Aspect | An angle inside one chart, or an angle between two charts (a synastry or cross-aspect), or an angle from today's sky to a natal chart (a transit). | Inside one chart on the birth chart, between two charts in the compatibility tool. The third sense — transits to your natal chart — is not computed anywhere. |
| Orb | The tolerance allowed around an exact aspect, or, in older texts, a fixed allowance belonging to a planet rather than to an aspect. | The aspect tolerance, and only that. Zodiux gives every body the same allowance. |
| Decan | The Chaldean face (seven planets cycling across all 36 decans) or the triplicity decanate (the element's three rulers in order). | Both, named separately, because they agree on only 9 of 36. A site that prints one unlabelled has picked for you. |
| Element | Fire, Earth, Air or Water as a symbolic category, or the chemical sense. | The symbolic category. Nothing here is a claim about matter. |
If a definition on this page is wrong, or describes a Zodiux behaviour that does not match what the site actually does, that is a defect and we would like to know: hello@zodiux.io. Corrections get made and dated — editorial standards covers how.
Method. Definitions describe standard usage in Western tropical astrology and are written by the Zodiux editorial team against the same brief as the rest of the library: state the traditional meaning plainly, without prediction. Every claim in the third column about what Zodiux does or does not compute was read directly off the shipped code rather than from any description of it — public/chart.js for the bodies, orbs, retrograde test, Ascendant and glyph key; public/compat.js for the synastry tool; public/retro.js for the Mercury station scan; public/moon-sign.js for the Moon calculator; public/sign-daily.js for the sign pages' daily lunar line; sky-build.mjs and public/sky-today.js for the sky strip; build-pages.mjs for the static pair-page scoring and the decan rulers. The two counts that are arithmetic on that code — 9 of 36 decans where the two ruler schemes agree, and the 93 defined terms — were computed, not estimated. Astronomical figures (orbital periods, maximum elongations, the 29.53-day synodic month, the 18.6-year nodal cycle, precession of about 1° per 72 years, mean obliquity for 2020 and 2026) are standard published values, not Zodiux measurements.
Limits. A glossary compresses. Several of these terms carry two centuries of argument behind them, and a two-sentence definition necessarily takes a side on some of it — where astrologers genuinely disagree, the row says so rather than picking a winner quietly. Definitions here are for the Western tropical tradition only: Vedic, Chinese and other systems use overlapping words for different things and are not translated. The third column describes the free tools as they shipped on the date below; a code change can make a row stale, and this page is not automatically regenerated from the source it describes. Nothing here predicts anything, and defining a technique is not a claim that it works. Astrology on Zodiux is for reflection and entertainment — it is not advice, medical, legal or otherwise. Spotted a wrong definition, or a Zodiux behaviour described incorrectly? Email hello@zodiux.io and it gets fixed.
Sources.
- Astronomy Engine — Open-source implementation of the VSOP87 and NOVAS algorithms. Bundled both in the browser and in the build, and the source of every position quoted on the site. Byte fingerprints for both copies are published at data sources.
- Zodiux source code — public/chart.js (ten bodies, five orbs, eight-aspect cut, 24-hour retrograde test, fixed obliquity 23.4367°, wheel rotation, glyphs), public/compat.js (synastry across seven bodies at the same orbs), public/retro.js (station scan, −220 to +430 days), public/moon-sign.js, public/sign-daily.js (solar-house lunar line and its own phase buckets), sky-build.mjs with public/sky-today.js (phase windows, 0.98565°/day solar ingress), build-pages.mjs (pair-page scoring, 36 decans, Chaldean and triplicity rulers).
- Standard astronomical constants — Synodic month 29.53 days; nodal regression cycle 18.6 years; precession about 1° per 72 years, full circuit roughly 25,800 years; mean obliquity 23.4367° for 2020 and 23.4358° for mid-2026, decreasing about 0.013° per century.
- Zodiux methodology — The zodiac, house, orb and precision policies indexed throughout are stated in full at how Zodiux computes your chart and in the calculation walkthrough.
Written and reviewed by the Zodiux editorial team · Last reviewed · Editorial standards and corrections · Astrology is for reflection and entertainment, not advice.
Now read the words on a real chart
Definitions land better attached to something. Run your own chart free in the browser — ten bodies by sign and degree, your rising sign if you know your birth time, and your eight tightest aspects. It computes on your device: your birth details go nowhere unless you copy a share link or buy a report yourself.
What does ℞ mean next to a planet?
Retrograde: the planet appeared to be moving backwards through the zodiac at your birth moment. Zodiux decides it by one test — compare the body's ecliptic longitude with its longitude 24 hours earlier, and flag it if the number went down. Because that sample is a whole day wide, a planet stationing on your birthday can fall either way. The Sun and Moon are exempt in the code and can never be flagged.
Why does this glossary say Zodiux does not calculate things like houses, the Midheaven or Chiron?
Because it does not, and a glossary defining only the terms behind features we ship would be a product tour. Houses are a real disagreement — Placidus, Whole Sign and Koch put planets in different houses from identical birth data — so the free chart draws no cusps and says so rather than picking one quietly. The Midheaven, the Part of Fortune, the lunar nodes and Chiron are all left out on the same principle.
Is a sign the same thing as a constellation?
No. A sign is exactly 30° of ecliptic longitude, twelve of them measured from the March equinox point. The constellations along the ecliptic are unequal in width — roughly 7° of Scorpius against 44° of Virgo — and include a thirteenth, Ophiuchus. The recurring "astronomers say your sign changed" story is this difference, restated as news roughly once a decade.
What orbs does Zodiux use, and why does that matter?
Seven degrees for the conjunction, trine and opposition, six for the square, five for the sextile — the same five windows in the birth chart and in the synastry tool, with no widening for the luminaries. It matters because an orb is a convention, not a measurement: widen it and a chart appears to have more aspects, narrow it and some disappear. Note that Zodiux uses the orb to rank and cut the list at eight but never prints the figure, so you cannot read tightness off the screen.
My Vedic chart gives different signs. Which one is wrong?
Neither, in its own terms. Zodiux uses the tropical zodiac, measured from the March equinox; Vedic astrology uses the sidereal zodiac, measured against the constellations. The two are currently about 24° apart because of precession, which is enough to move most placements back one sign. They are different coordinate conventions applied to the same sky, not a calculation error in either.
Which of these terms should I learn first?
Sign, ecliptic longitude, aspect and orb. Those four are enough to read your own placements list and check the arithmetic behind any aspect it reports. The big three — Sun, Moon and rising — is the usual entry point for interpretation, and the rising sign is the one that actually needs your birth time.