polyethylene vs synthetic resin

polyethylene and synthetic resin both are nouns.

Word	Noun	Adjective	Verb	Adverb
polyethylene	Yes	No	No	No
synthetic resin	Yes	No	No	No

As nouns, synthetic resin is a hypernym of polyethylene; that is, synthetic resin is a word with a broader meaning than polyethylene:

polyethylene: a lightweight thermoplastic; used especially in packaging and insulation
synthetic resin: a resin having a polymeric structure; especially a resin in the raw state; used chiefly in plastics

polyethylene (noun)	synthetic resin (noun)
a lightweight thermoplastic; used especially in packaging and insulation	a resin having a polymeric structure; especially a resin in the raw state; used chiefly in plastics