webpage vs home page

webpage and home page both are nouns.

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

As nouns, home page is a hyponym of webpage; that is, home page is a word with a more specific, narrower meaning than webpage:

webpage: a document connected to the World Wide Web and viewable by anyone connected to the internet who has a web browser
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)

Other hyponyms of webpage include homepage.

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