flower vs bud

flower and bud both are nouns.

Word	Noun	Adjective	Verb	Adverb
flower	Yes	No	Yes	No
bud	Yes	No	Yes	No

As nouns, bud is a hyponym of flower; that is, bud is a word with a more specific, narrower meaning than flower:

flower: reproductive organ of angiosperm plants especially one having showy or colorful parts
bud: a partially opened flower

flower (noun)	bud (noun)
a plant cultivated for its blooms or blossoms	a swelling on a plant stem consisting of overlapping immature leaves or petals
reproductive organ of angiosperm plants especially one having showy or colorful parts	a partially opened flower
the period of greatest prosperity or productivity

flower (verb)	bud (verb)
produce or yield flowers	develop buds
	start to grow or develop