binominal vs binomial

binominal is not a noun while binomial is a noun.

Word	Noun	Adjective	Verb	Adverb
binominal	No	Yes	No	No
binomial	Yes	Yes	No	No

As adjectives, binominal and binomial are synonyms defined as:

binominal and binomial: having or characterized by two names, especially those of genus and species in taxonomies

binominal (noun)	binomial (noun)
	(mathematics) a quantity expressed as a sum or difference of two terms; a polynomial with two terms

binominal (adjective)	binomial (adjective)
having or characterized by two names, especially those of genus and species in taxonomies	of or relating to or consisting of two terms
	having or characterized by two names, especially those of genus and species in taxonomies