web site vs newsgroup

web site and newsgroup both are nouns.

Word	Noun	Adjective	Verb	Adverb
web site	Yes	No	No	No
newsgroup	Yes	No	No	No

As nouns, newsgroup is a hyponym of web site; that is, newsgroup is a word with a more specific, narrower meaning than web site:

web site: a computer connected to the internet that maintains a series of web pages on the World Wide Web; a computer connected to the internet that maintains a series of web pages on the World Wide Web
newsgroup: an area on a computer network, especially on the internet, devoted to the discussion of a specified topic

Other hyponyms of web site include chat room, chatroom, portal, portal site, social networking service.

web site (noun)	newsgroup (noun)
a computer connected to the internet that maintains a series of web pages on the World Wide Web; a computer connected to the internet that maintains a series of web pages on the World Wide Web	an area on a computer network, especially on the internet, devoted to the discussion of a specified topic