Source : Webster's Revised Unabridged Dictionary (1913)

Quartenylic \Quar"ten*yl"ic\, a. [Quartene + -yl + -ic.] (Chem.)
   Pertaining to, or designating, an acid of the acrylic acid
   series, metameric with crotonic acid, and obtained as a
   colorless liquid; -- so called from having four carbon atoms
   in the molecule. Called also isocrotonic acid.