The name Katie is a girl's name of English, Greek origin meaning "pure". Katie is ranked #409 on our popularity charts and is often added to lists like Nicknames for Baby Girls and discussed in our forums with posts like "Heaven Hell or Purgatory- Girls".
From the experts:
Friendly mega-popular short form of Katherine that has definitively replaced Kathy, Katie is often given on its own. Going forward, though, Katie is more stylishly clipped itself to the grownup Kate.