Plain-language reference
Zodiac and Astrology Glossary
Hit a word you don't know? Look it up here. Each definition links to the guide where the term comes up, so you can see it in use.
Chart basics
Birth chart
A chart of celestial positions for a specific time and place.
Sun sign
The zodiac sign containing the Sun in a birth chart.
Ascendant
The zodiac degree rising on the eastern horizon.
Midheaven
An important chart angle associated with the upper meridian.
House
One of twelve chart sectors used for areas of interpretation.
Aspect
An angular relationship between chart factors.
Orb
The allowed distance from an exact aspect angle.
Zodiac structure
Zodiac
A coordinate or symbolic framework organized around the ecliptic.
Element
Fire, Earth, Air or Water in the four-element sign system.
Modality
Cardinal, Fixed or Mutable.
Ruling planet
A traditional association connecting planets and zodiac signs.
Decan
A ten-degree subdivision of a zodiac sign.
Cusp
A boundary between chart sectors or, informally, sign-change dates.
Astronomy and calculation terms
Ecliptic
The Sun’s apparent annual path on the celestial sphere.
Constellation
An officially defined region of the sky in modern astronomy.
Ephemeris
A table or dataset of calculated celestial positions.
Ingress
The moment a body enters a new sign or sector.
Retrograde
Apparent backward motion against the background sky.
Ayanamsa
An offset used in sidereal zodiac calculations.
Where to go next
If a definition is not enough, use the learning path for a structured introduction, Birth Chart hub for chart structure, or Zodiac Systems for tropical, sidereal and constellation distinctions.