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]

Moby Thesaurus II by Grady Ward, 1.0:

79 Moby Thesaurus words for "G":
   C, C-note, G suit, G-note, M, apogeotropism, buck, cartwheel, cent,
   century, chiliad, chiliagon, chiliahedron, chiliarch, chiliarchia,
   copper, dime, dollar, dollar bill, fifty cents, fin, fish,
   five cents, five hundred dollars, five-dollar bill,
   five-hundred-dollar bill, five-spot, fiver, four bits, frogskin,
   geotropism, grand, gravitation, graviton, gravity, half G,
   half a C, half dollar, half grand, hundred-dollar bill, iron man,
   kilo, kilocycle, kilogram, kilohertz, kiloliter, kilometer, lakh,
   mass, mill, millennium, millepede, milligram, milliliter, myriad,
   nickel, one hundred thousand, penny, quarter, red cent, sawbuck,
   silver dollar, skin, smacker, specific gravity, ten cents,
   ten thousand, ten-spot, tenner, thou, thousand, thousand dollars,
   thousand-dollar bill, twenty-dollar bill, twenty-five cents,
   two bits, two-dollar bill, two-spot, yard