Cilium

noun

(L. cilium: eyelid, eyelash, eyebrow) (pl. cilia) A small hair or hairlike process, usually along the margin of a structure. In unicellular plants, gametes, spores etc., minute hair-like protoplasmic protrusions whose movement confers motility on the cell; in higher plants, hairs more or less confined to the margins of an organ. In mosses, a delicate, hair-like or thread-like structure mostly one cell wide and unbranched (opposed to lacinia); in peristomes the structures frequently found singly or in groups alternating with the segments of the inner peristome; also applied to hair-like appendages fringing leaves or calyptrae.