Noun
A thick head of flowers on a very short axis, as a clover top, or a dandelion; a composite flower. A capitulum may be either globular or flat.
A knoblike protuberance of any part, esp. at the end of a bone or cartilage. [See Illust. of Artiodactyla.]
Source: Webster's dictionarya head of cauliflower Source: Internet
a head of lettuce Source: Internet