Source : Webster's Revised Unabridged Dictionary (1913)

Emerald \Em"er*ald\, n. [OE. emeraude, OF. esmeraude, esmeralde,
   F. ['e]meraude, L. smaragdus, fr. Gr. ?; cf. ?kr. marakata.]
   1. (Min.) A precious stone of a rich green color, a variety
      of beryl. See {Beryl}.

   2. (Print.) A kind of type, in size between minion and
      nonpare?l. It is used by English printers.

   Note: [hand] This line is printed in the type called emerald.

Emerald \Em"er*ald\, a.
   Of a rich green color, like that of the emerald. ``Emerald
   meadows.'' --Byron.

   {Emerald fish} (Zo["o]l.), a fish of the Gulf of Mexico
      ({Gobionellus oceanicus}), remarkable for the brilliant
      green and blue color of the base of the tongue; -- whence
      the name; -- called also {esmeralda}.

   {Emerald green}, a very durable pigment, of a vivid light
      green color, made from the arseniate of copper; green
      bice; Scheele's green; -- also used adjectively; as,
      emerald green crystals.

   {Emerald Isle}, a name given to Ireland on account of the
      brightness of its verdure.

   {Emerald spodumene}, or {Lithia emerald}. (Min.) See
      {Hiddenite}.

   {Emerald nickel}. (Min.) See {Zaratite}.

Source : WordNet®

emerald
     n 1: a green transparent form of beryl; highly valued as a
          gemstone
     2: a transparent piece of emerald that has been cut and
        polished and is valued as a precious gem
     3: the green color of an emerald

Source : Free On-Line Dictionary of Computing

Emerald
     
        An {object-oriented} distributed programming language and
        environment developed at the {University of Washington} in the
        early 1980s.  Emeral was the successor to {EPL}.  It is
        {strongly typed} and uses {signature}s and {prototype}s rather
        than {inheritance}.
     
        ["Distribution and Abstract Types in Emerald", A. Black et al,
        IEEE Trans Soft Eng SE-13(1):65-76 (Jan 1987)].
     
        (1994-11-09)