The name Calista is a girl's name of Greek origin meaning "most beautiful". Calista and is often added to lists like Unique Baby Names: Unusual and Rare and discussed in our forums with posts like "Quick Question Thread?!".
From the experts:
Spelled with either one 'l' or two, Calista came to the fore in 1997 when Calista Flockhart hit it big as Ally McBeal. Flockhart, who bears her mother's middle name, didn't just introduce a name, she introduced a whole sensibility. Pretty and delicate, Calista is definitely worthy of consideration, especially for parents with Greek roots.
In ancient myth, Calista (or Calisto)was a nymph loved by Zeus, whose jealous wife Hera turned her into a bear.