1715, from Latin cilia, plural of cilium "eyelid, eyelash," perhaps related to celare "to cover, hide," from PIE root *kel- "to conceal" (see cell), but words for this part of the face can be tricky (see brow). It sometimes is pluralized in English, which is an error. Related: Ciliated; ciliary; ciliate.
1. My tireless little cilia make about ten sweeping strokes a second.
2. Healthy, skin, mucous membranes, and cilia are natural barriers to many viruses.
3. Epithelium can also bear cilia.
4. Microtubules are also used in the construction of centrioles , basal bodies , cilia and flagella.
5. This is an unfortunate name, because they are not cilia but long protoplasmic extensions.