a colorless, poisonous, highly flammable gaseous hydrocarbon, HC⋮CH, produced by the reaction of water and calcium carbide: used in organic compound synthesis, for lighting, and with oxygen in welding: the simplest alkyne
See acetylene in American Heritage Dictionary 4
(ə-sĕtˈl-ēnˌ, -ən)
noun
A colorless, highly flammable or explosive gas, C2H2, used for metal welding and cutting and as an illuminant. Also called ethyne.