sb. pl. Sing. cilium, not common. [L. cilia, pl. of cilium, an eyelid, eyelid-edge, eyelash. (The plural has been made ciliæ and cilias by those who mistook cilia for a sing.) Cf. CIL.]
1. The eyelids, esp. the outer edges of the eyelids.
1715. Kersey, Cilium, the Eye-lid, properly the utmost Edge of the Eye-lid, out of which the Hairs grow.
So 1721–1800. Bailey.
1783. J. C. Smyth, in Med. Commun., I. 193. The cilia, or edges of the eye-lids, look red.
b. The eye-lashes.
1838. Penny Cycl., X. 141/2. The lashes or cilia … grow in several rows at the margins of both lids.
1875. H. Walton, Dis. Eye, 137. A cilium is always in the centre of it.
2. Delicate hairs resembling eye-lashes, esp. such as form a fringe on the margins of leaves, the wings of some insects, etc.
1794. Martyn, Rousseau’s Bot., xxvi. 402. The scales are ovate with erect capillary cilias.
1834. McMurtrie, Cuvier’s Anim. Kingd., 461. The wings [of diptera] are always distant…. Their edge is more or less fringed with cilia.
1875. Bennett & Dyer, trans. Sachs’ Bot., 331. The margin of the theca appears furnished with appendages of very regular form arranged in one or two rows … termed Teeth or Cilia.
3. Phys. Minute hair-like organs or appendages found on the tissues of most animals, and in some vegetable organisms. They are in incessant vibratile movement, and in many of the lower animal forms that live in water they serve as the chief organs of locomotion.
1835–6. Todd, Cycl. Anat., I. 606/1. The cilia serve as organs of locomotion. Ibid. Cilia … exist in a great many invertebrated and in all vertebrated animals except Fishes.
1872. Huxley, Physiol., vii. 157. In some of the lower animals, cells may be found possessing only a single cilium.
1875. Bennett & Dyer, trans. Sachs’ Bot., 211. Algae, The rotating advancing movement is occasioned by Cilia, fine vibratile threads which are sometimes very numerous but short, and cover the whole surface of the swarm-spore.
1881. Mivart, Cat, 26. Thread-like processes or cilia, which are capable of performing repeatedly a whipping-like movement.
4. in Comb. as cilia-bearing adj. (in sense 3).
1835–6. Todd, Cycl. Anat., I. 43/2. The cilia-bearing arches.
