acetylene

noun

1. (countable)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   “The acetylene gas lighting in the station offices and platforms at Kyle of Lochalsh recently has been replaced by electric lighting.”

2. (uncountable)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. (countable, uncountable)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.”