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]

The Collaborative International Dictionary of English v.0.48:

Sol \Sol\, n. [L.]
   1. The sun.
      [1913 Webster]

   2. (Alchem.) Gold; -- so called from its brilliancy, color,
      and value. --Chaucer.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sol \Sol\, n. [It.] (Mus.)
      (a) A syllable applied in solmization to the note G, or to
          the fifth tone of any diatonic scale.
      (b) The tone itself.
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sol \Sol\, n. [See Sou.]
   1. A sou.
      [1913 Webster]

   2. A silver and gold coin of Peru. The silver sol is the unit
      of value, and is worth about 68 cents.
      [1913 Webster] Sol

The Collaborative International Dictionary of English v.0.48:

Sol \Sol\ Sole \Sole\, n. [From hydrosol an aqueous colloidal
   solution, confused with G. sole, soole, salt water from which
   salt is obtained.] (Chem.)
   A fluid mixture of a colloid and a liquid; a liquid colloidal
   solution or suspension.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

sol
    n 1: a colloid that has a continuous liquid phase in which a
         solid is suspended in a liquid [syn: sol, colloidal
         solution, colloidal suspension]
    2: (Roman mythology) ancient Roman god; personification of the
       sun; counterpart of Greek Helios
    3: the syllable naming the fifth (dominant) note of any musical
       scale in solmization [syn: sol, soh, so]

V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

SOL
       Simulation-Oriented Language


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

SOL

   1.  Simulation Oriented Language.

   2. Second-Order lambda-calculus.

   3. Semantic Operating Language.  Language for manipulating
   semantic networks for building cognitive models, particularly
   for natural language understanding.  "Explorations in
   Cognition", D.A. Norman et al, W.H.  Freeman 1974.

   4. Shit Outta Luck.