The name Jon is a boy's name of Hebrew origin meaning "God is gracious; or gift of Jehovah". Jon is ranked #741 on our popularity charts and is often added to lists like Middle Names for Boys and discussed in our forums with posts like "Boys Makeover- Two Middles".
From the experts:
Streamlined version of the classic boys' names, sometimes a short form of Jonathan, which is in fact an entirely different name from John attached to a different Biblical personage. Jon feels more modern than the traditional John, but some may find it an overly slight variation on an already slim name. Jon Snow is a popular character on HBO's Game of Thrones.