The authority of all bros. Although this person is "the authority" he is still super chill and usually welcomes worthy outsiders into his circle of bros. This term was introduced in the south park episode "Broadway Bro Down," which originally aired 10/26/11. The term was used by randy marsh participating in a bro fight with Stephen Schwartz who then replies saying that his famous musicals clearly make him the brothority.
by TheChillbro October 27, 2011