The Collaborative International Dictionary of English v.0.48:

Colt pistol \Colt pistol\ (Firearms)
   A self-loading or semi-automatic pistol with removable
   magazine in the handle holding seven cartridges. The recoil
   extracts and ejects the empty cartridge case, and reloads
   ready for another shot. Called also Browning pistol,
   Colt-Browning pistol, automatic pistol and automatic.
   [Webster 1913 Suppl. +PJC]

The Collaborative International Dictionary of English v.0.48:

Automatic \Au`to*mat"ic\, Automatical \Au`to*mat"ic*al\, a. [Cf.
   F. automatique. See Automaton.]
   1. Having an inherent power of action or motion.
      [1913 Webster]

            Nothing can be said to be automatic.  --Sir H. Davy.
      [1913 Webster]

   2. Pertaining to, or produced by, an automaton; of the nature
      of an automaton; self-acting or self-regulating under
      fixed conditions; operating with minimal human
      intervention; -- esp. applied to machinery or devices in
      which certain things formerly or usually done by hand are
      done by the machine or device itself; as, the automatic
      feed of a lathe; automatic gas lighting; an automatic
      engine or switch; an automatic mouse; an automatic
      transmission. The opposite of manual.

   Note: Narrower terms are: autoloading(prenominal),
         semiautomatic ; {automated, machine-controlled,
         machine-driven ; {self-acting, self-activating,
         self-moving, self-regulating ; {self-locking ;
         {self-winding . Also See: mechanical.
         [1913 Webster + WordNet 1.5]

   3. (Physiol.) Not voluntary; not depending on the will;
      mechanical; controlled by the autonomic nervous system;
      without conscious control; as, automatic movements or
      functions. The opposite of {voluntary.

   Syn: reflex(prenominal), reflexive,involuntary
        [1913 Webster + WordNet 1.5]

              Unconscious or automatic reasoning. --H. Spenser.
        [1913 Webster]

   4. like the unthinking functioning of a machine. an automatic
      `thank you'

   Syn: automaton-like, automatonlike, machinelike,
        machine-like, robotlike.
        [WordNet 1.5]

   Automatic arts, such economic arts or manufacture as are
      carried on by self-acting machinery. --Ure.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

automatic \automatic\ n.
   1. light machine gun.

   Syn: automatic rifle, machine rifle
        [WordNet 1.5]

   2. a pistol that will keep firing until the ammunition is
      gone or the trigger is released; as, a .45 automatic.

   Syn: automatic pistol.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

automatic
    adj 1: operating with minimal human intervention; independent of
           external control; "automatic transmission"; "a budget
           deficit that caused automatic spending cuts" [ant:
           manual]
    2: resembling the unthinking functioning of a machine; "an
       automatic `thank you'"; "machinelike efficiency" [syn:
       automatic, automatonlike, machinelike, robotlike,
       robotic]
    3: without volition or conscious control; "the automatic
       shrinking of the pupils of the eye in strong light"; "a
       reflex knee jerk"; "sneezing is reflexive" [syn: automatic,
       reflex(a), reflexive]
    n 1: light machine gun [syn: automatic rifle, automatic,
         machine rifle]
    2: a pistol that will keep firing until the ammunition is gone
       or the trigger is released [syn: automatic pistol,
       automatic]

Moby Thesaurus II by Grady Ward, 1.0:

155 Moby Thesaurus words for "automatic":
   accordant, accustomed, alike, automated, automatic device,
   automaton, automatous, balanced, beaten, blind, blowgun, blowpipe,
   casual, compulsive, conditioned, confirmed, consistent, consonant,
   constant, continuous, correspondent, cybernated, cyborg, equable,
   equal, even, firearm, flamethrower, flat, forced, frequent, gat,
   gun, gut, habitual, habituated, hackneyed, handgun, heater,
   homogeneous, ill-advised, ill-considered, ill-devised, immutable,
   impulsive, inadvertent, indeliberate, ineluctable, inescapable,
   inevitable, inherent, innate, instinctive, instinctual, invariable,
   involuntary, level, libidinal, measured, mechanical,
   mechanical man, methodic, monolithic, musket, natural, of a piece,
   ordered, orderly, peashooter, persistent, piece, pistol, prompt,
   quick, ready, recurrent, recurring, reflex, reflexive, regular,
   repeater, repetitive, revolver, rifle, robot, robotlike, rod,
   routine, sawed-off shotgun, self-acting, self-active,
   self-adjusting, self-closing, self-controlled, self-cooking,
   self-directed, self-directing, self-dumping, self-governed,
   self-governing, self-lighting, self-mover, self-operative,
   self-regulating, self-regulative, self-starting, self-winding,
   self-working, semiautomatic, shooting iron, shotgun, six-gun,
   six-shooter, smooth, snap, spontaneous, stable, steadfast, steady,
   stereotyped, subliminal, systematic, trite, unadvised, unavoidable,
   unbroken, uncalculated, unchangeable, unchanged, unchanging,
   unconscious, unconsidered, undeliberate, undeliberated, undesigned,
   undeviating, undifferentiated, undiversified, uniform, unintended,
   unintentional, unlearned, unmeditated, unpremeditated, unprompted,
   unruffled, unstudied, unthinking, unvaried, unvarying, unwilled,
   unwilling, unwitting, well-trodden, well-worn