polythene vs polyethylene

polythene and polyethylene both are nouns.

Word	Noun	Adjective	Verb	Adverb
polythene	Yes	No	No	No
polyethylene	Yes	No	No	No

As nouns, polythene and polyethylene are synonyms defined as:

polythene and polyethylene: a lightweight thermoplastic; used especially in packaging and insulation

polythene (noun)	polyethylene (noun)
a lightweight thermoplastic; used especially in packaging and insulation	a lightweight thermoplastic; used especially in packaging and insulation