The Collaborative International Dictionary of English v.0.48:

Zest \Zest\, v. t. [imp. & p. p. Zested; p. pr. & vb. n.
   Zesting.]
   1. To cut into thin slips, as the peel of an orange, lemon,
      etc.; to squeeze, as peel, over the surface of anything.
      [1913 Webster]

   2. To give a relish or flavor to; to heighten the taste or
      relish of; as, to zest wine. --Gibber.
      [1913 Webster]