Capitulum

noun

1. A densely clustered inflorescence composed of a large number of individual florets arising from a platform-like base.
2. The head-like mouthpart apparatus of a tick, including the palpi, mandibles, and hypostome.
3. A small protuberance on a bone which articulates into another bone to form a ball-and-socket joint.
4. The enlarged end of a proboscis.