borrow pit vs cavity

borrow pit and cavity both are nouns.

Word	Noun	Adjective	Verb	Adverb
borrow pit	Yes	No	No	No
cavity	Yes	No	No	No

As nouns, cavity is a hypernym of borrow pit; that is, cavity is a word with a broader meaning than borrow pit:

borrow pit: a pit created to provide earth that can be used as fill at another site
cavity: a sizeable hole (usually in the ground)

Other hypernyms of borrow pit include pit.

borrow pit (noun)	cavity (noun)
a pit created to provide earth that can be used as fill at another site	(anatomy) a natural hollow or sinus within the body
	a sizeable hole (usually in the ground)
	soft decayed area in a tooth; progressive decay can lead to the death of a tooth
	space that is surrounded by something