Literally means 13 though. hence the gang affiliation. Mexican Mob. MS13. and etc.
Not the same as a Cholo... because a Cholo is NOT a gangster. They are just latino thugs (thugs = ppl all about themselves not the set).
Sur Trece usually wear kahkis with a button up that only has the top button buttoned (2 is the Trece is white, very rare ime)