What is the part-of-speech of "Google" in "Google Maps" or "Google Books"?

"Google Books" isn't a sentence, so they're not going to follow all of the grammatical rules. So it's a part of the subject, meaning both Google and Books are the subject (2-word subject). It's not perfect grammar, but whatever

Google is a search engine, maps and books are a branch of this directed from google, where your search only results in books and maps

Google is possibly from the word Googol, which is a number!

if thats what you meant??