Decan

Definition

A decan is one of three ten-degree sections within a zodiac sign. Because every sign spans thirty degrees, its first decan covers 0–9 degrees, the second covers 10–19 degrees, and the third covers 20–29 degrees. Traditional astrology also calls decans “faces” and assigns a planetary ruler to each section.

Astrological Meaning

Decans add a secondary layer of detail to a sign placement without replacing the sign’s fundamental meaning. A planet in the first, second, or third decan may express the sign’s qualities with a different emphasis based on that decan’s ruler. Several rulership systems exist. Traditional face rulers follow an established planetary sequence, while many modern astrologers connect each decan with signs or planetary rulers from the same element. Interpretations therefore depend on the system being used and should be considered alongside the planet, house, aspects, dignity, and overall natal chart.

Why It Matters

Decans help astrologers distinguish between placements that share the same zodiac sign but occupy different degrees. They can provide useful nuance in natal interpretation, timing methods, and some forms of predictive astrology. Their influence is generally treated as a refinement rather than a dominant factor, making decans most valuable when they reinforce themes already visible elsewhere in the chart.

Related Encyclopedia Entries

• Natal Chart
• Astrology Techniques
• Predictive Astrology