Kira is the Russian feminine of Cyrus — from the Greek Kyros, meaning "lord" or possibly from the Persian word for "sun." In Japanese, 煌 (kira) means "sparkle" or "glitter."
Kira entered the U.S. top 1000 in 1981 and has been continuously used. The character Kira in The Dark Crystal and Kira Nerys in Star Trek: Deep Space Nine are notable bearers.
Kira 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 Kira reduce to 3, The Communicator. This is a traditional interpretive system, not a factual claim about the name.