The Collaborative International Dictionary of English v.0.48:

Gat \Gat\ (g[a^]t),
   imp. of Get. [Obs.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Get \Get\ (g[e^]t), v. t. [imp. Got (g[o^]t) (Obs. Gat
   (g[a^]t)); p. p. Got (Obsolescent Gotten (g[o^]t"t'n));
   p. pr. & vb. n. Getting.] [OE. geten, AS. gitan, gietan (in
   comp.); akin to Icel. geta, Goth. bigitan to find, L.
   prehendere to seize, take, Gr. chanda`nein to hold, contain.
   Cf. Comprehend, Enterprise, Forget, Impregnable,
   Prehensile.]
   1. To procure; to obtain; to gain possession of; to acquire;
      to earn; to obtain as a price or reward; to come by; to
      win, by almost any means; as, to get favor by kindness; to
      get wealth by industry and economy; to get land by
      purchase, etc.
      [1913 Webster]

   2. Hence, with have and had, to come into or be in possession
      of; to have. --Johnson.
      [1913 Webster]

            Thou hast got the face of man.        --Herbert.
      [1913 Webster]

   3. To beget; to procreate; to generate.
      [1913 Webster]

            I had rather to adopt a child than get it. --Shak.
      [1913 Webster]

   4. To obtain mental possession of; to learn; to commit to
      memory; to memorize; as to get a lesson; also with out;
      as, to get out one's Greek lesson.
      [1913 Webster]

            It being harder with him to get one sermon by heart,
            than to pen twenty.                   --Bp. Fell.
      [1913 Webster]

   5. To prevail on; to induce; to persuade.
      [1913 Webster]

            Get him to say his prayers.           --Shak.
      [1913 Webster]

   6. To procure to be, or to cause to be in any state or
      condition; -- with a following participle.
      [1913 Webster]

            Those things I bid you do; get them dispatched.
                                                  --Shak.
      [1913 Webster]

   7. To betake; to remove; -- in a reflexive use.
      [1913 Webster]

            Get thee out from this land.          --Gen. xxxi.
                                                  13.
      [1913 Webster]

            He . . . got himself . . . to the strong town of
            Mega.                                 --Knolles.
      [1913 Webster]

   Note: Get, as a transitive verb, is combined with adverbs
         implying motion, to express the causing to, or the
         effecting in, the object of the verb, of the kind of
         motion indicated by the preposition; thus, to get in,
         to cause to enter, to bring under shelter; as, to get
         in the hay; to get out, to make come forth, to extract;
         to get off, to take off, to remove; to get together, to
         cause to come together, to collect.
         [1913 Webster]

   To get by heart, to commit to memory.

   To get the better of, To get the best of, to obtain an
      advantage over; to surpass; to subdue.

   To get up, to cause to be established or to exit; to
      prepare; to arrange; to construct; to invent; as, to get
      up a celebration, a machine, a book, an agitation.

   Syn: To obtain; gain; win; acquire. See Obtain.
        [1913 Webster]

WordNet (r) 3.0 (2006):

gat
    n 1: a gangster's pistol [syn: gat, rod]

Moby Thesaurus II by Grady Ward, 1.0:

59 Moby Thesaurus words for "gat":
   aperture, automatic, blowgun, blowpipe, broaching, cavity, chasm,
   check, clearing, cleft, crack, disclosure, fenestra, firearm,
   fistula, flamethrower, fontanel, foramen, gap, gape, gulf, gun,
   handgun, heater, hiatus, hole, hollow, inlet, interval, lacuna,
   laying open, leak, musket, opening, opening up, orifice, outlet,
   passageway, peashooter, piece, pistol, pore, repeater, revolver,
   rifle, rod, sawed-off shotgun, shooting iron, shotgun, six-gun,
   six-shooter, slot, space, split, stoma, throwing open, uncorking,
   unstopping, yawn



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

GAT

   Generalized Algebraic Translator.  Improved version of IT.  On
   IBM 650 RAMAC.

   [Sammet 1969, p. 142].