Basically the same as "homie" "Holmes" "N*gga" Whatever floats your boat, i don't mean the N word rascally, just as another synonym for "homie". I just personally think Duco sounds better, i recall hearing it more in NYC and origins may be of mexican or latin (american) heritage).
******side note, some use as one of those words you can replace any noun with the said word...(duco).
