cilia (n.)youdaoicibaDictYouDict[cilia 词源字典]
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.[cilia etymology, cilia origin, 英语词源]