The Collaborative International Dictionary of English v.0.48:

Cockney \Cock"ney\ (k[o^]k"n[y^]), n.; pl. Cockneys (-n[i^]z).
   [OE. cocknay, cokenay, a spoiled child, effeminate person, an
   egg; prob. orig. a cock's egg, a small imperfect egg; OE. cok
   cock + nay, neye, for ey egg (cf. Newt), AS. [ae]g. See 1st
   Cock, Egg, n.]
   1. An effeminate person; a spoilt child. "A young heir or
      cockney, that is his mother's darling." --Nash (1592).
      [1913 Webster]

            This great lubber, the world, will prove a cockney.
                                                  --Shak.
      [1913 Webster]

   2. A native or resident of the city of London, especially one
      living in the East End district; -- sometimes used
      contemptuously.
      [1913 Webster +PJC]

            A cockney in a rural village was stared at as much
            as if he had entered a kraal of Hottentots.
                                                  --Macaulay.
      [1913 Webster]

   3. the distinctive dialect of a cockney[2].
      [PJC]