The Collaborative International Dictionary of English v.0.48:

G \G\ (j[=e])
   1. G is the seventh letter of the English alphabet, and a
      vocal consonant. It has two sounds; one simple, as in
      gave, go, gull; the other compound (like that of j), as in
      gem, gin, dingy. See Guide to Pronunciation, [sect][sect]
      231-6, 155, 176, 178, 179, 196, 211, 246.
      [1913 Webster]

   Note: The form of G is from the Latin, in the alphabet which
         it first appeared as a modified form of C. The name is
         also from the Latin, and probably comes to us through
         the French. Etymologically it is most closely related
         to a c hard, k y, and w; as in corn, grain, kernel; kin
         L. genus, Gr. ?; E. garden, yard; drag, draw; also to
         ch and h; as in get, prehensile; guest, host (an army);
         gall, choler; gust, choose. See C.
         [1913 Webster]

   2. (Mus.) G is the name of the fifth tone of the natural or
      model scale; -- called also sol by the Italians and
      French. It was also originally used as the treble clef,
      and has gradually changed into the character represented
      in the margin. See Clef. G[sharp] (G sharp) is a tone
      intermediate between G and A.
      [1913 Webster]