It literally translates to "little friend," but it's used specifically to refer to a girlfriend.
Here are some other options, though they are slightly less common:
* "copine": This is a more informal and casual term, often used among friends.
* "amoureuse": This is a more formal and poetic term, meaning "lover."
* "fiancée": This means "fiancée," which is a specific term for a woman who is engaged to be married.
The best option will depend on the context and your relationship with the person you are talking to.