speedboat vs hydroplane

speedboat and hydroplane both are nouns.

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

As nouns, hydroplane is a hyponym of speedboat; that is, hydroplane is a word with a more specific, narrower meaning than speedboat:

speedboat: a fast motorboat
hydroplane: a speedboat that is equipped with winglike structures that lift it so that it skims the water at high speeds

Other hyponyms of speedboat include hydrofoil.

speedboat (noun)	hydroplane (noun)
a fast motorboat	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

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