May be the most modern, stylish Catherine nickname: more unusual than Kate or Cate, with an animal and word name edge. Cat Power is a trendy folksinger.

As Theo and Thea get more popular, so do Teo and Tea, short forms of the Latinate variations of Theodore and Matthew -- which include Dorotea and Mattea. But like Theo and Thea, Tea can stand perfectly well on its own and blends seamlessly into any Anglophone or European culture, if that is your aim. Some may argue that the Tea version is the prettiest and it's certainly the sleekest.