What, asks the columnist Philologus in the online magazine Mosaic, is the difference between a kippah and a yarmulke? I’m glad he supplied an answer, for I know no Yiddish and less Hebrew, and the Oxford English Dictionary is reticent.
Kippah first appeared in the OED in 1997, with the bare etymology ‘from Hebrew’. Philologus observes that it denotes ‘any skullcap worn by a Jew for religious reasons’. He suggests that kippah derives from a word in early rabbinic Hebrew (from the time of the compilation of the Mishnah, the first century in AD-dating). That Hebrew word meant ‘dome’ or ‘vault’, either of a building or of the heavens. This sounds a satisfying derivation.
But Philologus introduces the possibility that kippah in the sense ‘cap’ comes from the Latin cappa, which gave us the English cap, once meaning ‘hood’ or ‘cloak with a hood’, until it settled down in the Middle Ages to mean ‘brimless male head-dress’.
As for yarmulke, a Yiddish word, Philologus notes that it ‘generally refers only to the sewn satin or felt cap, commonly with a cotton lining, of Ashkenazi Eastern Europe’. He mentions that it is often traced back to a Polish word — as the OED does, deriving it from jarmulka, ‘cap’. But Philologus thinks the borrowing is in the other direction, from Yiddish to Polish.
He favours instead an origin put forward by W. Gunther Plaut (1912–2012), who suggested the medieval Latin almucia. In English, amice is a confusing word, since the liturgical vestment that covers the shoulders and sometimes the head comes from a different Latin word, amictus, while the word we’re interested in, almucia, meant a fur hood. It seems that the latter word, which shares an origin with the Scottish word mutch, ‘cap’, had acquired the prefix al-, the Arabic definite article, even though it was not an Arabic word. Anyway, Philologus is convinced by an origin of yarmulke from almucella, a diminutive of almucia.
So if you see a round Jewish head-covering being worn, it is not wrong to call it a kippah. Philologus has one piece of advice: if you don’t want to sound mocking, pronounce kippah with the stress on the second syllable. I shall do so gratefully.