lamprey

Lamprey comes from Middle English laumprei, from Old French lampreie, from Medieval Latin lampreda, likely an alteration of Late Latin lampetra, whose deeper origin is unknown but is traditionally explained as lambō ("to lick, lap") plus petra ("stone, rock").

The word passed from Late Latin into Medieval Latin, then into Old French, and finally into Middle English with only minor spelling shifts along the way.

It's a doublet of limpet, another word rooted in Latin, meaning the two English words descend from a shared Latin source despite sounding quite different today.