cross bit vs borer

cross bit and borer both are nouns.

Word	Noun	Adjective	Verb	Adverb
cross bit	Yes	No	No	No
borer	Yes	No	No	No

As nouns, borer is a hypernym of cross bit; that is, borer is a word with a broader meaning than cross bit:

Other hypernyms of cross bit include bore bit, rock drill, stone drill.

cross bit (noun)	borer (noun)
a rock drill having cruciform cutting edges; used in mining	any of various insects or larvae or mollusks that bore into wood
	a drill for penetrating rock