biennial vs annual

biennial and annual both are nouns.

Word	Noun	Adjective	Verb	Adverb
biennial	Yes	Yes	No	No
annual	Yes	Yes	No	No

biennial (noun)	annual (noun)
(botany) a plant having a life cycle that normally takes two seasons from germination to death to complete; flowering biennials usually bloom and fruit in the second season	a reference book that is published regularly once every year
	(botany) a plant that completes its entire life cycle within the space of a year

biennial (adjective)	annual (adjective)
having a life cycle lasting two seasons	completing its life cycle within a year
occurring every second year	occurring or payable every year