The Collaborative International Dictionary of English v.0.48:

Elaidic \E`la*id"ic\, a. [Cf. F. ['e]la["i]dique. See Elaine.]
   Relating to oleic acid, or elaine.
   [1913 Webster]

   Elaidic acid (Chem.), a fatty acid isomeric with oleic
      acid, and obtained from it by the action of nitrous acid.
      [1913 Webster]