While the Classical Latin etymon of the fruit is considered to be prunum, the derivations of this word in Germanic languages demonstrate a phonological development from pr- to pl- that is difficult to explain (see the OED entry plum for a fuller discussion). Forms in pl- are attested from the Old English period and it seems that medieval British Latin created the form plumus as a borrowing. The chronology suggests the AN attestations of this word should be considered borrowings of the ME or Latin term.