bloom vs period of time

bloom and period of time both are nouns.

Word	Noun	Adjective	Verb	Adverb
bloom	Yes	No	Yes	No
period of time	Yes	No	No	No

As nouns, period of time is a hypernym of bloom; that is, period of time is a word with a broader meaning than bloom:

Other hypernyms of bloom include period, time period.

bloom (noun)	period of time (noun)
a powdery deposit on a surface	an amount of time
reproductive organ of angiosperm plants especially one having showy or colorful parts
the organic process of bearing flowers
a rosy color (especially in the cheeks) taken as a sign of good health
the best time of youth
the period of greatest prosperity or productivity

bloom (verb)	period of time (verb)
produce or yield flowers