Decan
Glossary · Last updated: 2026-07-26
Each zodiac sign is divided into three decans of ten degrees each. Decans add a sub-ruler planet and nuance beyond broad sun-sign blurbs.
Decans matter most when you know exact birth degree from a full chart. Date-only tools usually stay at whole-sign level.
Historical layers
Hellenistic and Egyptian decan lore fed medieval astrology. Modern apps rarely surface decans unless you open detailed chart software.