tv vs television set

tv and television set both are nouns.

Word	Noun	Adjective	Verb	Adverb
tv	Yes	No	No	No
television set	Yes	No	No	No

As nouns, tv and television set are synonyms defined as:

tv and television set: an electronic device that receives television signals and displays them on a screen

Other synonyms of tv include boob tube, goggle box, idiot box, television, television receiver, telly, tv set.

tv (noun)	television set (noun)
an electronic device that receives television signals and displays them on a screen	an electronic device that receives television signals and displays them on a screen