acetylene

noun3

1. •
   Any organic compound having one or more carbon–carbon triple bonds; an alkyne.

   • The acetylene gas lighting in the station offices and platforms at Kyle of Lochalsh recently has been replaced by electric lighting. — 1951
2. •
   Ethyne; the simplest alkyne, a hydrocarbon of formula HC≡CH. It is a colourless, odourless, extremely flammable, explosive gas, formerly used as an illuminating gas, but now used in welding and metallurgy.
3. •
   A lamp powered by acetylene, particularly a motor vehicle headlight.

   • Mrs. Winnie had kindly sent her limousine car for them, and it stood throbbing in front of the hotel-entrance, its acetylenes streaming far up the street. — 1908