What is that mean leto in Italian language?

"Leto" in Italian doesn't have a direct meaning, but it is a proper noun. It is the Italian spelling of "Letó", the Greek name of "Latona", the mother of Apollo and Artemis in Roman mythology.

Therefore, "Leto" in Italian primarily refers to Latona, the goddess.

It's possible you may have come across "Leto" in a different context. Could you please provide more information about where you saw this word? I might be able to give you a more specific answer.