flower vs period of time

flower and period of time both are nouns.

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

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

Other hypernyms of flower include period, time period.

flower (noun)	period of time (noun)
a plant cultivated for its blooms or blossoms	an amount of time
reproductive organ of angiosperm plants especially one having showy or colorful parts
the period of greatest prosperity or productivity

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