Decan

Each zodiac sign is divided into three decans (also called decanates or faces) of 10 degrees each. Each decan is assigned a planetary sub-ruler, adding a secondary layer of meaning to a planet's sign placement. For example, the first decan of Aries (0-10 degrees) is ruled by Mars, the second (10-20) by the Sun, and the third (20-30) by Venus, in the Chaldean system. Decans provide fine-grained nuance, explaining why two people with the same Sun sign can feel quite different. They are also used as a minor essential dignity.