floatplane vs hydroplane

floatplane and hydroplane both are nouns.

Word	Noun	Adjective	Verb	Adverb
floatplane	Yes	No	No	No
hydroplane	Yes	No	Yes	No

As nouns, hydroplane is a hypernym of floatplane; that is, hydroplane is a word with a broader meaning than floatplane:

floatplane: a seaplane equipped with pontoons for landing or taking off from water
hydroplane: an airplane that can land on or take off from water

Other hypernyms of floatplane include seaplane.

floatplane (noun)	hydroplane (noun)
a seaplane equipped with pontoons for landing or taking off from water	an airplane that can land on or take off from water
	a speedboat that is equipped with winglike structures that lift it so that it skims the water at high speeds

floatplane (verb)	hydroplane (verb)
	glide on the water in a hydroplane