bow and arrow vs weapon

bow and arrow and weapon both are nouns.

Word	Noun	Adjective	Verb	Adverb
bow and arrow	Yes	No	No	No
weapon	Yes	No	No	No

As nouns, weapon is a hypernym of bow and arrow; that is, weapon is a word with a broader meaning than bow and arrow:

Other hypernyms of bow and arrow include arm, weapon system.

bow and arrow (noun)	weapon (noun)
a weapon consisting of arrows and the bow to shoot them	any instrument or instrumentality used in fighting or hunting
	a means of persuading or arguing