Decan — Definition

Each zodiac sign covers thirty degrees, and each thirty-degree slice is split into three ten-degree decans. Different traditions assign rulers to decans — Hellenistic astrology uses planetary rulers in a fixed sequence (the Chaldean order), while modern astrology often uses elemental rulers. Decans give astrologers a finer brush: a 4° Leo and a 24° Leo behave with the same Leo logic but in noticeably different keys.

Origin

From the Greek dekanos, "chief of ten." The decan system originated in ancient Egyptian star calendars.

Example

Someone with the Sun in the second decan of Capricorn (10°–19°) is often read as Capricorn flavoured with the practical earthiness of Taurus.