Astrology Glossary
Every essential astrology term explained in plain language. From the twelve houses and major aspects to lunar concepts, chart patterns, and predictive techniques —50+ definitions with the tradition behind them.
How to Use This Glossary
Astrology has a vocabulary that has built up over more than two thousand years — Hellenistic Greek roots, medieval Arabic and Latin elaborations, Renaissance Christian astrology, 19th-century Theosophical revivals, and 20th-century psychological reframings all sit on top of each other in modern practice. The result is a working language that can feel dense to anyone reading their first chart.
This glossary covers the terms you will run into most often. Each entry begins with a one-sentence definition, expands into a full paragraph of context, and ends with four or five frequently asked questions. Where a tradition is named — Robert Hand on transits, Liz Greene on outer planets, Demetra George on asteroids, William Lilly on horary — we name it so you can follow up at the source.
Astrology is descriptive, not prescriptive. The definitions you find here describe what symbols traditionally mean, not what your life must become. Whether you treat astrology as serious craft, reflective practice, or a language of metaphor, the vocabulary is the same.
Browse by Category
Seven categories, 50 terms. Jump to the section you need.
The 12 Houses
12 terms in this section.
- First House
- The house of self, beginning at the Ascendant; rules identity, appearance, and the persona you lead with.
- Second House
- The house of resources, values, and what you call your own — money, possessions, and self-worth.
- Third House
- The house of mind, communication, siblings, and the everyday environment — short trips and conversations.
- Fourth House
- The house of home, family, ancestry, and the inner emotional foundation — beginning at the IC.
- Fifth House
- The house of creativity, play, romance, and children — what you make purely because you want to.
- Sixth House
- The house of work, daily routines, service, and physical health — the structure of ordinary life.
- Seventh House
- The house of partnership — marriage, business partners, and open enemies; begins at the Descendant.
- Eighth House
- The house of shared resources, intimacy, transformation, death, and inheritance — the deep waters.
- Ninth House
- The house of philosophy, higher education, long journeys, and the search for meaning.
- Tenth House
- The house of career, public reputation, and life direction — begins at the Midheaven.
- Eleventh House
- The house of community, friendship, hopes, and the groups you belong to — the chosen tribe.
- Twelfth House
- The house of the unconscious, hidden things, solitude, and spiritual undercurrents — the dissolving edge of the chart.
Major Aspects
6 terms in this section.
- Conjunction
- Two planets within a few degrees of each other — they blend their energies and act as one combined force.
- Opposition
- Two planets 180° apart — sitting across the chart from each other, forming a polarity that asks for balance.
- Square
- Two planets 90° apart — a tense, friction-creating aspect that pushes for action and growth.
- Trine
- Two planets 120° apart — a flowing, harmonious aspect; the energies cooperate without resistance.
- Sextile
- Two planets 60° apart — a gentle, opportunity-creating aspect; cooperation requires a small push.
- Quincunx
- Two planets 150° apart — an awkward, adjustment-requiring aspect; the planets share no common ground.
Chart Components
8 terms in this section.
- Ascendant
- The zodiac degree rising on the eastern horizon at birth — your rising sign and the cusp of the First House.
- Descendant
- The zodiac degree setting on the western horizon at birth — the cusp of the Seventh House and the qualities you seek in partnership.
- Midheaven (MC)
- The highest point of the chart — the cusp of the Tenth House; describes career, public role, and life direction.
- Imum Coeli (IC)
- The lowest point of the chart — the cusp of the Fourth House; describes home, family, and inner foundation.
- North Node
- A mathematical point where the Moon’s orbit crosses the ecliptic going north — symbolises future-direction and growth.
- South Node
- The point opposite the North Node — symbolises familiar patterns, comfort zones, and what the soul is releasing.
- Lilith (Black Moon)
- A mathematical point representing the Moon’s apogee — read as the rebellious, untamed, shadow-feminine in modern astrology.
- Chiron
- A small celestial body between Saturn and Uranus, discovered in 1977 — read as “the wounded healer” in modern astrology.
Lunar Concepts
5 terms in this section.
- Void of Course Moon
- The period when the Moon has finished its last major aspect to another planet before changing signs.
- New Moon
- The moment when the Sun and Moon are conjunct — invisible from Earth, traditionally read as the start of a lunar cycle.
- Full Moon
- The moment when the Sun and Moon are in opposition — fully illuminated; traditionally read as culmination and release.
- Supermoon
- A full or new moon occurring near the Moon’s closest approach to Earth — visibly larger and astrologically amplified.
- Lunar Eclipse
- A full moon where Earth’s shadow falls across the Moon — traditionally read as an amplified, fated full moon.
Chart Patterns
6 terms in this section.
- Stellium
- Three or more planets clustered in the same sign or house of a birth chart — a major concentration of planetary energy.
- Yod
- Two planets in sextile, both quincunx to a third planet at the apex — “the Finger of God,” a fated-feeling pattern.
- Grand Trine
- Three planets forming a perfect triangle of 120° trines — a flowing gift of one element’s energy.
- Grand Cross
- Four planets forming two oppositions that square each other — a high-tension pattern in one quality (cardinal, fixed, or mutable).
- T-Square
- Three planets where two are in opposition and a third squares both — a high-pressure pattern with a single focal planet.
- Kite
- A grand trine plus a fourth planet opposing one trine point and sextiling the other two — a grand trine with built-in drive.
Predictive Techniques
5 terms in this section.
- Transit
- A planet’s current movement and the aspects it makes to your natal chart — the foundation of predictive astrology.
- Progressed Chart
- A symbolic forward-moved chart where one day after birth equals one year of life — used for inner development.
- Solar Return
- A chart cast for the moment the Sun returns to its natal position each year — read as the year’s themes.
- Synastry
- The technique of comparing two birth charts to study the relationship between two people.
- Composite Chart
- A single chart created by averaging two birth charts — represents the relationship itself as an independent entity.
Other Key Terms
8 terms in this section.
- Retrograde
- When a planet appears to move backward from Earth’s perspective — read as an inward, review-oriented phase.
- Shadow Period
- The weeks before and after a planet’s retrograde when it crosses the same zodiac degrees — themes preview and re-emerge.
- Ingress
- A planet’s entry into a new zodiac sign — read as the start of a new chapter for that planet’s themes.
- Ephemeris
- A table or database of planetary positions for every day — the working reference of astrological calculation.
- Sidereal vs Tropical
- Two zodiac systems — tropical (Western, tied to the seasons) and sidereal (Vedic, tied to the constellations).
- Decan
- A 10° subdivision of a zodiac sign — each sign has three decans, each with its own sub-ruler and flavour.
- Cusp
- The boundary between two adjacent zodiac signs or two adjacent houses — a transition line in the chart.
- Chart Ruler
- The planet that rules the zodiac sign on the Ascendant — treated as the chart’s lead actor.
Next Steps
Reading definitions is one thing; seeing them in your own chart is another. If you want to put this vocabulary to work, start with your birth chart — it puts every term on this page into the concrete geometry of your own life.