Laters

If you want to say good-bye to your friend, you can either say 'Bye' or 'See you later'.

To shorten 'See you later' you can say 'Laters'. It is a slang.

For example, listen to the following conversation.

John: I've got to get moving, Mums is waiting for me there.
Albert: Laters. [Meaning: See you later.]

By the way, though an 's' is added to mum, the meaning is still the same, that is 'my mother' or 'my mum'.