Cirri

Part of speech: noun

Definitions

1. Long, thin extensions from the bodies of specific marine creatures, utilized mainly for feeding and sometimes for movement in aquatic environments
2. Fine, filamentous structures present in particular aquatic organisms that facilitate feeding and contribute to mobility within their habitats
3. Slender, threadlike projections found on some water-dwelling creatures that assist in capturing food and sometimes aid in locomotion

Etymology: "Cirri" is the plural of "cirrus," and the Latin word it comes from was itself a fairly ordinary term for a curl or fringe. In Latin, "cirrus" referred to a curl of hair, and it also meant a tuft or fringe, the sort of loose, hanging thread that could appear on a garment or a plant. English took the plural "cirri" directly from Latin as a learned borrowing, which means it was adopted by scholars writing in English rather than passing through everyday speech or another language first. The leap from hair and fringes to sea creatures happened because the Latin term was applied descriptively to the thin, hair-like appendages of animals. Those marine appendages, which many crustaceans and sea spiders use to sweep food toward the mouth, looked enough like fine curled strands to earn the same name. The plural form "cirri" is the one most often seen in biology, where it refers to several such extensions at once.