marten

From Middle English martren, martryn, borrowed from Old French martrine, meaning 'marten fur,' which traces to Old Dutch *marthrīn, 'of marten fur,' from an underlying *marthar, 'marten.'

The word entered English already tied to the fur trade, naming the pelt before it settled onto the creature that wore it. In doing so, it pushed out the older native English word for the animal.

It displaced the Old English word mearþ, which came from Proto-Germanic *marþuz — the two are distant cousins from the same Germanic root, though only one survived into modern use.