osculation vs osculate

osculation is a noun but osculate is not a noun.

Word	Noun	Adjective	Verb	Adverb
osculation	Yes	No	No	No
osculate	No	No	Yes	No

osculation (noun)	osculate (noun)
the act of caressing with the lips (or an instance thereof)
(mathematics) a contact of two curves (or two surfaces) at which they have a common tangent

osculation (verb)	osculate (verb)
	touch with the lips or press the lips (against someone's mouth or other body part) as an expression of love, greeting, etc.
	have at least three points in common with
	be intermediate between two taxonomic groups