what is acetylene
acetylene. n. 1. (Elements & Compounds) a colourless flammable gas used in the manufacture of organic chemicals and in cutting and welding metals.. acetylene-a colorless flammable gas used chiefly in welding and in organic synthesis. alkyne, ethyne. aliphatic compound-organic compound that is an alkane or alkene or alkyne or their derivative. oxyacetylene-a mixture of oxygen and acetylene; used to create high temperatures for cutting or welding metals.