The Signs are classified by their Qualities: Cardinal, Fixed or Mutable. Also referred to as modalities or quadruplicities.
In addition to categorising the signs by element, astrologers place the twelve signs of the zodiac into three additional categories, or qualities: cardinal, mutable, or fixed. Each sign is considered to be a combination of its element and quality. Where the element of a sign describes its basic nature, the quality describes its mode of expression.
Division of the signs of the Zodiac into three categories: Cardinal, Fixed, and Mutable— related to specific attributes common to each category. Cardinal signs represent signs associated with beginnings; fixed signs are identified more with completion; mutable signs can go either way. Also known as the Quadruplicities.