Astrology Glossary

Interpretive limits: Astrology myths
Chart foundations: Natal chart

This glossary collects twenty common terms, each with a brief definition and a link to a related article. Terms help identify methods; interpretation still belongs in the context of a full chart, not as a verdict based on one word.

Twenty Terms

Term	One-line definition	Canonical page
Retrograde	Apparent backward motion	Retrograde planets
Shadow period	Degrees retraced before or after a retrograde	Mercury retrograde
Orb	The angular range in which an aspect is considered active	Orbs
Applying	Two planets moving toward an exact aspect	Transits
Separating	Two planets moving away from an exact aspect	Transits
Precession	A shift in coordinates caused by Earth’s axial wobble	Precession
Stellium	Three or more planets gathered in one sign or house	Stellium
Chart ruler	The planet ruling the Ascendant’s sign	Chart ruler
Aspect pattern	A fixed structure formed by several aspects	Aspect patterns
House overlay	One person’s planets falling in another person’s houses	House overlays
Eclipse	A new or full Moon near the lunar nodes	Eclipses
Lunation	The new Moon and full Moon cycle	Lunar phases
Secondary progression	One day symbolically corresponds to one year	Progressed Moon
Return	A planet returning to its natal position	Saturn return
Empty house	A house containing no planets	Empty houses
Birth time	Data that determines the angles and houses	Unknown birth time
Barnum effect	General statements perceived as personally specific	Barnum effect
Free will	The room for choice within tendencies	Fate and free will
Tropical zodiac	Zodiac measured from the March equinox	Tropical and sidereal zodiacs
Sidereal zodiac	Zodiac aligned with the stellar background	Tropical and sidereal zodiacs