two-man saw vs pitsaw

two-man saw and pitsaw both are nouns.

Word	Noun	Adjective	Verb	Adverb
two-man saw	Yes	No	No	No
pitsaw	Yes	No	No	No

As nouns, pitsaw is a hyponym of two-man saw; that is, pitsaw is a word with a more specific, narrower meaning than two-man saw:

two-man saw: a saw with handles at both ends; intended for use by two people
pitsaw: a large two-handed saw formerly used to cut logs into planks; one man stood above the log and the other in a pit below

two-man saw (noun)	pitsaw (noun)
a saw with handles at both ends; intended for use by two people	a large two-handed saw formerly used to cut logs into planks; one man stood above the log and the other in a pit below