birdhouse vs shelter

birdhouse and shelter both are nouns.

Word	Noun	Adjective	Verb	Adverb
birdhouse	Yes	No	No	No
shelter	Yes	No	Yes	No

As nouns, shelter is a hypernym of birdhouse; that is, shelter is a word with a broader meaning than birdhouse:

birdhouse (noun)	shelter (noun)
a shelter for birds	a structure that provides privacy and protection from danger
	protective covering that provides protection from the weather
	temporary housing for homeless or displaced persons
	a way of organizing business to reduce the taxes it must pay on current earnings
	the condition of being protected

birdhouse (verb)	shelter (verb)
	invest (money) so that it is not taxable
	provide shelter for