Quick answer
Leonidas is a boy name.
Meaning and history
This name is derived from Greek λέων ( leon ) meaning "lion" combined with the patronymic suffix ἴδης ( ides ). Leonidas was a Spartan king of the 5th century BC who sacrificed his life and his army defending the pass of Thermopylae from the Persians. This was also the name of a 3rd-century saint and martyr, the father of Origen, from Alexandria.
Notes and context
Usage: greek, ancient greek | Greek: Λεωνίδας