mulberry

The word comes from Middle English mulbery, molberye, or murberie, partly from Old English mōrberġe, and probably partly from Middle Low German mulbere. Both ultimately trace to a Proto-West Germanic form combining Latin mōrus with Proto-West Germanic *baʀi ('berry').

The facts don't show a shift in meaning — the word seems to have referred to the same fruit throughout its history, only its spelling and pronunciation shifting as it passed from Old English through Middle English forms.

It's a cousin of Dutch moerbezie/moerbei and German Maulbeere, both descending from the same Proto-West Germanic root, and it shares its second half with the ordinary English word 'berry.'