Calista comes from the Greek kallistos (κάλλιστος), meaning "most beautiful" — the superlative of kalos (beautiful). In Greek mythology, Callisto was a nymph beloved of Zeus, later transformed into the constellation Ursa Major.
Calista has been rising in the U.S. Today it sits in the U.S. top 700 and is climbing.
Calista does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Calista reduce to 2, The Peacemaker. This is a traditional interpretive system, not a factual claim about the name.