The Collaborative International Dictionary of English v.0.48:

Undecolic \Un`de*col"ic\, a. [Undecylenic + propiolic.] (Chem.)
   Pertaining to, or designating, an acid, C11H18O2, of the
   propiolic acid series, obtained indirectly from undecylenic
   acid as a white crystalline substance.
   [1913 Webster]