The female equivalent of the slang term brah, used colloquially to refer to one's close female chums. 'Hah' is a modified version of the slang term ho in much the same way brah is a modified version of the slang term bro. Although ho typically refers to women in a derogatory sense, 'hah' is meant to convey the same friendly kinship as brah.
Friend #1: 'Sup, hah! How's it hangin'?
(Female) Friend #2: It isn't hanging. Most of my sexual organs are firmly situated inside my abdomen.