As far as I know, the two characters 东西 used together can convey two meanings , either east and west or a thing. I wonder if it's just due to an homophony. The word dong-xi ( an object ) would have been written with the two characters by sound-loan. Instead, is it possible to hypothesize that the compound originates from the two monosyllabic words ? If so, it would be necessary to figure out how it can be derived from these two words. Thanks for any enlightenment.