lighter vs houseboat

lighter and houseboat both are nouns.

Word	Noun	Adjective	Verb	Adverb
lighter	Yes	No	Yes	No
houseboat	Yes	No	No	No

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

Other hyponyms of lighter include dredger, pontoon, scow, Norfolk wherry, wherry.

lighter (noun)	houseboat (noun)
a device for lighting or igniting fuel or charges or fires	a barge that is designed and equipped for use as a dwelling
a flatbottom boat for carrying heavy loads (especially on canals)
a substance used to ignite or kindle a fire

lighter (verb)	houseboat (verb)
transport in a flatbottom boat