home page vs webpage

home page and webpage both are nouns.

Word	Noun	Adjective	Verb	Adverb
home page	Yes	No	No	No
webpage	Yes	No	No	No

As nouns, webpage is a hypernym of home page; that is, webpage is a word with a broader meaning than home page:

home page: the opening page of a web site; also, the first page opened when a web browser is launched (default or start-up page)
webpage: a document connected to the World Wide Web and viewable by anyone connected to the internet who has a web browser

Other hypernyms of home page include web page.

home page (noun)	webpage (noun)
the opening page of a web site; also, the first page opened when a web browser is launched (default or start-up page)	a document connected to the World Wide Web and viewable by anyone connected to the internet who has a web browser