[n] a colorless flammable gas used chiefly in welding and in organic synthesis
\A*cet"y*lene\, n. (Chem.) A gaseous compound of carbon and hydrogen, in the proportion of two atoms of the former to two of the latter. It is a colorless gas, with a peculiar, unpleasant odor, and is produced for use as an illuminating gas in a number of ways, but chiefly by the action of water on calcium carbide. Its light is very brilliant. --Watts.