television channel vs TV channel

television channel and TV channel both are nouns.

Word	Noun	Adjective	Verb	Adverb
television channel	Yes	No	No	No
TV channel	Yes	No	No	No

As nouns, television channel and TV channel are synonyms defined as:

television channel and TV channel: a television station and its programs

Other synonyms of television channel include channel.

television channel (noun)	TV channel (noun)
a television station and its programs	a television station and its programs