French kiss vs osculation

French kiss and osculation both are nouns.

Word	Noun	Adjective	Verb	Adverb
French kiss	Yes	No	No	No
osculation	Yes	No	No	No

As nouns, osculation is a hypernym of French kiss; that is, osculation is a word with a broader meaning than French kiss:

French kiss: an openmouthed kiss in which your tongue is inserted into the other's mouth
osculation: the act of caressing with the lips (or an instance thereof)

Other hypernyms of French kiss include buss, kiss.

French kiss (noun)	osculation (noun)
an openmouthed kiss in which your tongue is inserted into the other's mouth	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