uncinus

Century Dictionary and Cyclopedia

1. n. A hook or hooklet; a hamulus; something small, hard, and crooked; specifically, in conchology, one of the uncinal teeth of the radula.
2. n. One of the hooked cilia of infusorians.
3. n. One of the numerous minute chitinous hooks of the tori of some annelids. See Uncinata.
4. n. A weapon used in the eleventh century, resembling a martel-de-fer, but thought to have only one point or edge.

Wiktionary

1. n. meteorology A cloud species which consists of fine hair-like strands, with hooked terminations. Associated only with cirrus formations.
2. n. paleontology The curved tip of the hooks associated with belemnite tentacles.

GNU Webster's 1913

1. n. (Zoöl.) One of the peculiar minute chitinous hooks found in large numbers in the tori of tubicolous annelids belonging to the Uncinata.