Leo \leo\ as a boy's name is pronounced LEE-oh. It is of Latin origin, and the meaning of Leo is "lion". A common name in Roman times, and the name of 13 popes, including Leo the Great (fifth century), who successfully dealt with Attila the Hun when the Vandals conquered Rome. Author Leo Tolstoy; actor Leo G. Carroll.
Leo has 9 variant forms: Lee, Leon, Leoncio, Leonel, Leonello, Leontios, Lev, Lion and Lyon.
For more information, see also related names Leomaris, Leander, Leonard and Leopold.