BRAN, the ground husk of wheat, oats, barley or other cereals, used for feeding cattle, packing and other purposes (see Flour). The word occurs in French bren or bran, in the dialects of other Romanic languages, and also in Celtic, cf. Breton brenn, Gaelic bran. The New English Dictionary considers these Celtic forms to be borrowed from French or English. In modern French bren means filth, refuse, and this points to some connexion with Celtic words, e.g. Irish brean, manure. If so, the original meaning would be refuse. "Bran-new," i.e. quite new, is now the common form of "brand-new," that which is fresh from the "brand," the branding-iron used for marking objects, etc.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)