ca·pit·u·lum 
(kə-pĭchə-ləm)
(kə-pĭchə-ləm)n. pl. ca·pit·u·la (-lə)
1. A compact cluster of sessile flowers, often surrounded by involucral bracts, as of daisies and other composite plants.
2. A small knob or head-shaped part, such as a protuberance of a bone or the tip of an insect's antenna.
[Latin, diminutive of caput, capit-, head; see kaput- in the Appendix of Indo-European roots.]