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]

WordNet (r) 3.0 (2006):

g
    n 1: a metric unit of weight equal to one thousandth of a
         kilogram [syn: gram, gramme, gm, g]
    2: a purine base found in DNA and RNA; pairs with cytosine [syn:
       guanine, G]
    3: one of the four nucleotides used in building DNA; all four
       nucleotides have a common phosphate group and a sugar
       (ribose) [syn: deoxyguanosine monophosphate, G]
    4: the cardinal number that is the product of 10 and 100 [syn:
       thousand, one thousand, 1000, M, K, chiliad, G,
       grand, thou, yard]
    5: a unit of force equal to the force exerted by gravity; used
       to indicate the force to which a body is subjected when it is
       accelerated [syn: g, gee, g-force]
    6: a unit of information equal to 1000 megabytes or 10^9
       (1,000,000,000) bytes [syn: gigabyte, G, GB]
    7: a unit of information equal to 1024 mebibytes or 2^30
       (1,073,741,824) bytes [syn: gigabyte, gibibyte, G,
       GB, GiB]
    8: (physics) the universal constant relating force to mass and
       distance in Newton's law of gravitation [syn: gravitational
       constant, universal gravitational constant, constant of
       gravitation, G]
    9: the 7th letter of the Roman alphabet [syn: G, g]

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



The Jargon File (version 4.4.7, 29 Dec 2003):

G
 pref.,suff.

    1. [SI] See quantifiers.

    2. The letter G has special significance in the hacker community, largely
    thanks to the GNU project and the GPL.

    Many free software projects have names that names that begin with G. The
    GNU project gave many of its projects names that were acronyms beginning
    with the word ?GNU?, such as ?GNU C Compiler? (gcc) and ?GNU Debugger?
    (gdb), and this launched a tradition. Just as many Java developers will
    begin their projects with J, many free software developers will begin
    theirs with G. It is often the case that a program with a G-prefixed name
    is licensed under the GNU GPL.

    For example, someone may write a free Enterprise Engineering Kludge package
    (EEK technology is all the rage in the technical journals) and name it ?
    geek? to imply that it is a GPL'd EEK package.


The Free On-line Dictionary of Computing (30 December 2018):

G

   1.  The abbreviated form of giga-.

   2.  ["G: A Functional Language with Generic Abstract
   Data Types", P.A.G. Bailes, Computer Langs 12(2):69-94, 1987].

   3.  A language developed at Oregon State
   University in 1988 which combines functional programming,
   object-oriented programming, relational, imperative
   programming and logic programming (you name it we got it).

   ["The Multiparadigm Language G", J. Placer, Computer Langs
   16:235-258, 1991].

   [Jargon File]

   (1996-08-12)