An alkyne is an unsaturated hydrocarbon that contains a carbon–carbon triple bond (C≡C). The triple bond is the functional group, making alkynes more reactive than alkanes and a useful building block in synthesis. In nomenclature the parent chain takes the suffix '-yne'; for example, the simplest alkyne, ethyne (commonly called acetylene), contrasts with the double-bonded alkene and the single-bonded alkane of the same carbon count.

炔烃是含有碳碳三键(C≡C)的不饱和烃。该三键即为官能团,使炔烃比烷烃更活泼,并成为合成中有用的结构单元。在命名中,主链以词尾“-yne(炔)”表示;例如最简单的炔烃乙炔(俗称电石气)与相同碳数的含双键烯烃及含单键烷烃形成对照。