The OED, the bulwark of the English language, is ever-expanding (and some may argue ever-eroding) with the addition of new terms that aim to keep pace with technological and social change.
This month, among entries like "big data" and "fracking," the OED Online is also proud to include terms like "slow jam" (a slow, smooth, romantic song, sometimes with a strongly sexual feel) and "bra," which is, yes, slang for "bro".
In case you are confused about how to use "bra" (also, "brah") in a sentence, the OED has a few helpful examples:
a male friend or associate:
his brahs are giving him major props
used as a familiar form of address for a man:
(Bra) used as an informal title before a man’s name:
Now, quick! Someone please alert the Wall Street Journal.