There are multiple origins and meanings for the name:
1. Latin name, meaning - "the Moon"
2. Alchemical name of silver
In Roman mythology Luna is the divine embodiment of the Moon. She is often presented as the female complement of the Sun. Luna is not always a distinct goddess, but sometimes rather an epithet that specializes a goddess, since both Diana and Juno are identified as moon goddesses. Greek form - Selene.