noun, plural: cirri

(botany) A tendril or clasper or similar part.


(1) A bundle or tuft of cilia serving as foot or tentacle in certain ciliate protozoa.

(2) An eversible copulatory organ of male flatworms and other invertebrates.

(3) A protuberance in the upper lip where the nasolabial groove terminates in a salamander head.

(4) The hair of certain animals (e.g. dog, horse) that is coarse and longer than the normal coat yet less coarse than tactile hairs.

(meteorology) A type of cloud characterized by thin, wisplike strands, often accompanied by tufts, thus, commonly referred to as ‘’mare's tail’’.


In salamanders the cirri are more prominent among males, and are believed to be involved in courtship.

In flatworms, the cirrus is an eversible copulatory apparatus. If it is not eversible, then it is called a penis.

Word origin: Latin, a curl, tuft, plant filament like a tuft of hair.
Related forms: cirrous (adjective)

Related terms:

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