Movatterモバイル変換

fossil word

From Wiktionary, the free dictionary

Probably from the fact that afossil was once a living organism, but is still of historical and scientific interest.

Examples
ado, as inwithout further ado ormuch ado about nothing fro, as into and fro yore, as inof yore

fossil word (pluralfossil words)

(linguistics) A word that is broadlyobsolete but remains in current use because it is contained within anidiom that is still in use.