mirror

Mirror comes from Middle English mirour, from Old French mireor, literally "looker, watcher," from mirer ("to look at"), from Latin mīror ("to wonder at"), from mīrus ("wonderful"), ultimately from Proto-Indo-European *smey- ("to laugh, to be glad").

The word displaced a native Old English term, sċēawere, which meant both "mirror" and "spy" — so English once had a homegrown word for the reflective glass before borrowing this one from French.

Mirror shares its root with words built on Latin mīrus, since both trace back to the idea of something wonderful enough to make you stare.