Source : Webster's Revised Unabridged Dictionary (1913)

Elaidic \E`la*id"ic\, a. [Cf. F. ['e]la["i]dique. See {Elaine}.]
   Relating to oleic acid, or elaine.

   {Elaidic acid} (Chem.), a fatty acid isomeric with oleic
      acid, and obtained from it by the action of nitrous acid.

Source : WordNet®

elaidic acid
     n : a monounsaturated fatty acid that has the same structure as
         oleic acid except that it is a trans fatty acid; the
         major trans fatty acid in margarine and fried foods