web tv vs TV

web tv and TV both are nouns.

Word	Noun	Adjective	Verb	Adverb
web tv	Yes	No	No	No
TV	Yes	No	No	No

As nouns, TV is a hypernym of web tv; that is, TV is a word with a broader meaning than web tv:

web tv: the genre of original television content produced for broadcast via the World Wide Web.
TV: broadcasting visual images of stationary or moving objects

Other hypernyms of web tv include telecasting, television, video.

web tv (noun)	TV (noun)
the genre of original television content produced for broadcast via the World Wide Web.	broadcasting visual images of stationary or moving objects