bloom (n.1)

"blossom of a plant," c. 1200, a northern word, from a Scandinavian source akin to Old Norse blomi "flower, blossom," also collectively "flowers and foliage on trees;" from Proto-Germanic *blomon (source also of Old Saxon blomo, Middle Dutch bloeme, Dutch bloem, Old High German bluomo, German Blume, Gothic bloma), from PIE *bhle- (source also of Old Irish blath "blossom, flower," Latin flos "flower," florere "to blossom, flourish"), extended form of root *bhel- (3) "to thrive, bloom." Related to Old English blowan "to flower" (see blow (v.2)).

Not extended like 'flower' to a whole 'flowering plant', and expressing a more delicate notion than 'blossom', which is more commonly florescence bearing promise of fruit, while 'bloom' is florescence thought of as the culminating beauty of the plant. Cherry trees are said to be in blossom, hyacinths in bloom. [OED]

Transferred sense, of persons, "pre-eminence, superiority," is from c. 1300; meaning "state of greatest loveliness" is from early 14c.; that of "blush on the cheeks" is from 1752. Old English had cognate bloma, but only in the figurative sense of "state of greatest beauty;" the main word in Old English for "flower" was blostm (see blossom (n.)).

bloom (n.2)

"rough mass of wrought iron," from Old English bloma "lump of metal; mass," which is of unknown origin. Identical in form to bloom (n.1), and sometimes regarded as a secondary sense of it, but evidence of a connection is wanting.

bloom (v.)

mid-13c., blomen, "bear flowers, blossom, be in flower," from an Old Norse noun from the same source as bloom (n.1). Related: Bloomed; blooming.

updated on September 25, 2018

Definitions of bloom from WordNet
bloom (n.)
the organic process of bearing flowers;
you will stop all bloom if you let the flowers go to seed
Synonyms: blooming
bloom (n.)
reproductive organ of angiosperm plants especially one having showy or colorful parts;
Synonyms: flower / blossom
bloom (n.)
the best time of youth;
Synonyms: bloom of youth / salad days
bloom (n.)
a rosy color (especially in the cheeks) taken as a sign of good health;
Synonyms: blush / flush / rosiness
bloom (n.)
the period of greatest prosperity or productivity;
bloom (n.)
a powdery deposit on a surface;
Synonyms: efflorescence
bloom (v.)
produce or yield flowers;
The cherry tree bloomed
Synonyms: blossom / flower
Etymologies are not definitions. From, not affiliated with etymonline.