backsaw vs carpenter's saw

backsaw and carpenter's saw both are nouns.

Word	Noun	Adjective	Verb	Adverb
backsaw	Yes	No	No	No
carpenter's saw	Yes	No	No	No

As nouns, carpenter's saw is a hypernym of backsaw; that is, carpenter's saw is a word with a broader meaning than backsaw:

backsaw: a handsaw that is stiffened by metal reinforcement along the upper edge
carpenter's saw: a saw used with one hand for cutting wood

Other hypernyms of backsaw include hand saw, handsaw.

backsaw (noun)	carpenter's saw (noun)
a handsaw that is stiffened by metal reinforcement along the upper edge	a saw used with one hand for cutting wood