Bilbo

I have always been under the impression that "Bilbo" was taken from the noun, "a rapier or sword", which comes from the word "Bilbao", in Spain.

Actually, the only source stating the connection to a sword is Ruth Noel's Languages of Middle-Earth, a book that is outdated and unauthorative. In Tolkiens universe, Bilbo is from Bilba, which is of unknown meaning, like the main entry says.