The Collaborative International Dictionary of English v.0.48:

Mocha \Mo"cha\, n.
   1. A seaport town of Yemen, on the Red Sea, also spelled
      Mukha.
      [1913 Webster]

   2. A variety of coffee originally brought from Mocha.
      [1913 Webster]

   3. An Abyssinian weight, equivalent to a Troy grain.
      [1913 Webster]

   4. A flavoring made from an infusion of coffee or of a
      combination of coffee with chocolate or cocoa.
      [PJC]

   5. A color of a deep chocolate brown.
      [PJC]

   Mocha stone (Min.), moss agate.
      [1913 Webster]

WordNet (r) 3.0 (2006):

mocha
    n 1: soft suede glove leather from goatskin
    2: a flavoring made from coffee mixed with chocolate
    3: a superior dark coffee made from beans from Arabia [syn:
       mocha, mocha coffee]
    4: a dark brown color