cross-fertilise vs fertilize

cross-fertilise and fertilize both are verbs.

Word	Noun	Adjective	Verb	Adverb
cross-fertilise	No	No	Yes	No
fertilize	No	No	Yes	No

As verbs, fertilize is a hypernym of cross-fertilise; that is, fertilize is a word with a broader meaning than cross-fertilise:

Other hypernyms of cross-fertilise include fecundate, fertilise, inseminate.

cross-fertilise (verb)	fertilize (verb)
cause to undergo cross-fertilization	introduce semen into (a female)
undergo cross-fertilization; become fertile	provide with fertilizers or add nutrients to
	make fertile or productive