What is "valylene"

Valylene \Val"yl*ene\, n. [Valerian + -yl.] (Chem.) A volatile liquid hydrocarbon, C5H6, related to ethylene and acetylene, but possessing the property of unsaturation in the third degree. It is the only known member of a distinct series of compounds. It has a garlic odor.

n. (context organic compound English) The organic compound ''2-methylbut-1-en-3-yne'' HC≡C-C(CH₃)=CH₂