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Birth chart
A map of planetary positions at a birth moment and place. An exact time also determines the rising sign and houses.
Read the guide →Short answers, deeper guides
Astrology Glossary: 20 Essential Terms
Twenty starting points for the language of astrology. Each definition leads to a guide that explains the subject; close variants share a useful destination rather than duplicated pages. Read calculated sky data separately from traditional interpretation.
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Natal chart
Another name for a birth chart. Despite the name, a natal chart primarily plots planets, signs, houses and aspects.
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Rising sign
The zodiac degree rising on the eastern horizon at birth. It needs a reliable birth time and place.
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Moon sign
The Moon's zodiac sign at birth. Birth time matters near the days when the Moon changes sign.
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Venus sign
Venus's natal sign, traditionally read in relation to taste, values and how a person approaches affection.
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Zodiac compatibility
A simple comparison of two Sun signs. A fuller relationship reading compares both birth charts.
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Composite chart
A relationship chart formed from the midpoints of two people's planetary positions, distinct from synastry.
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Electional astrology
The tradition of comparing sky conditions before starting an activity. Timing cannot replace practical preparation.
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Solar return
A chart cast for the yearly moment when the Sun returns to its natal degree.
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Astrological transits
A comparison of current planetary positions with a fixed natal chart.
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Saturn return
Saturn's return to its natal position after roughly 29.4 years; it is better understood as a period than one date.
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Mercury retrograde
Mercury's apparent backward motion as seen from Earth. The planet does not reverse its orbit.
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Void-of-course Moon
The interval before a Moon sign change in which it makes no further major aspect under the chosen tradition.
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Moon phases
The roughly 29.5-day Sun–Moon angle cycle, distinct from a person's natal Moon sign.
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Astrocartography
An astrology technique mapping where planets were angular around the world at the birth moment.
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Astrological houses
The twelve chart divisions traditionally linked to areas of life. Their boundaries depend on birth time and house system.
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Astrological aspects
Angular relationships between planetary longitudes; conjunction, square and trine are common examples.
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Unknown birth time
Most planetary signs remain calculable, while the Ascendant, houses and sometimes Moon sign remain uncertain.
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New Moon
The phase when Sun and Moon share nearly the same ecliptic longitude; the Moon is usually not visible.
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Full Moon
The phase when Sun and Moon are approximately 180 degrees apart in zodiacal longitude.
Read the guide →For synastry and horary, continue with the separate guides to relationship chart comparison and question-time charts. Once you know the terms, compare them with the placements in your own birth chart; do not base important life decisions only on an astrological interpretation.