borer vs straight flute

borer and straight flute both are nouns.

Word	Noun	Adjective	Verb	Adverb
borer	Yes	No	No	No
straight flute	Yes	No	No	No

As nouns, straight flute is a hyponym of borer; that is, straight flute is a word with a more specific, narrower meaning than borer:

Other hyponyms of borer include cross bit, star drill, straight-fluted drill.

borer (noun)	straight flute (noun)
any of various insects or larvae or mollusks that bore into wood	a rock drill with flutes that are straight
a drill for penetrating rock