Decan — Astrology glossary

A decan is a ten-degree division of a zodiac sign, splitting each sign's 30 degrees into three equal segments. Each decan is associated with a sub-ruler that shades the sign's expression. In a natal chart, knowing which decan a planet falls in refines its meaning beyond the sign alone, since the three decans of one sign carry distinct flavours. It matters because it explains why two people with the same Sun sign can feel noticeably different. For example, a Sun in the final decan of Leo is often read as carrying a more idealistic, outward-looking tone than a Sun in the first decan. Astrologers use decans to add precision, drawing on either the modern planetary rulers or older traditions tracing back to Egyptian sky lore.