cola nut vs kola nut

cola nut and kola nut both are nouns.

Word	Noun	Adjective	Verb	Adverb
cola nut	Yes	No	No	No
kola nut	Yes	No	No	No

As nouns, cola nut and kola nut are synonyms defined as:

cola nut and kola nut: bitter brown seed containing caffein; source of cola extract

cola nut (noun)	kola nut (noun)
bitter brown seed containing caffein; source of cola extract	tree bearing large brown nuts containing e.g. caffeine; source of cola extract
	bitter brown seed containing caffein; source of cola extract