Blossom
Old English blōstm, blōstma (noun), blōstmian (verb), of Germanic origin; related to Dutch bloesem, also to bloom1.
wiktionary
From Middle English blosme, from Old English blōstm, blōstma, from Proto-Germanic *blōsmaz (compare West Frisian blossem, bloesem), an enlargement of *blōstaz (compare German Blust), from Proto-Indo-European *bʰleh₃-s-(“ bloom, flower”), from *bʰleh₃-(“to bloom, to thrive”). Cognate with Albanian bleron(“to blossom, to thrive”), Latin flōs(“flower”), Flōra(“ goddess of plants”). See more at blow (etymology 4).
etymonline
blossom (n.)
c. 1200, from Old English blostm, blostma "a flower of a plant," from Proto-Germanic *blo-s- (source also of Middle Low German blosom, Dutch bloesem, German Blust), from PIE *bhlow-, extended form of root *bhel- (3) "to thrive, bloom." This is the native word, now largely superseded by bloom (n.1) from Old Norse and flower (n.) from French.
blossom (v.)
late 14c., from Old English blostmian "put forth blossoms, to flower," from blostma "a blossom, a flower" (see blossom (n.)). Figurative use from late 14c. Related: Blossomed; blossoming.
