1. (in anatomy) A small rounded head of a bone that articulates with another bone.

2. (in botany) A type of flowering shoot (see racemose inflorescence) characteristic of plants of the family Compositae (Asteraceae), e.g. daisy and dandelion. The tip of the shoot is flattened and bears many small stalkless flowers (florets) surrounded by an involucre (ring) of bracts. This arrangement gives the appearance of a single flower.

3. (in zoology) The palps and mouthparts of a tick.