shears vs scissors

shears and scissors both are nouns.

Word	Noun	Adjective	Verb	Adverb
shears	Yes	No	No	No
scissors	Yes	No	No	No

As nouns, scissors is a hypernym of shears; that is, scissors is a word with a broader meaning than shears:

Other hypernyms of shears include pair of scissors.

shears (noun)	scissors (noun)
large scissors with strong blades	a wrestling hold in which you wrap your legs around the opponents body or head and put your feet together and squeeze
	a gymnastic exercise performed on the pommel horse when the gymnast moves his legs as the blades of scissors move
	an edge tool having two crossed pivoting blades