The Collaborative International Dictionary of English v.0.48:

Throttle \Throt"tle\, n. [Dim. of throat. See Throat.]
   1. The windpipe, or trachea; the weasand. --Sir W. Scott.
      [1913 Webster]

   2. (Steam Engine) The throttle valve.
      [1913 Webster]

   Throttle lever (Steam Engine), the hand lever by which a
      throttle valve is moved, especially in a locomotive.

   Throttle valve (Steam Engine), a valve moved by hand or by
      a governor for regulating the supply of steam to the steam
      chest. In one form it consists of a disk turning on a
      transverse axis.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Throttle \Throt"tle\, v. t. [imp. & p. p. Throttled; p. pr. &
   vb. n. Throttling.]
   1. To compress the throat of; to choke; to strangle.
      [1913 Webster]

            Grant him this, and the Parliament hath no more
            freedom than if it sat in his noose, which, when he
            pleases to draw together with one twitch of his
            negative, shall throttle a whole nation, to the wish
            of Caligula, in one neck.             --Milton.
      [1913 Webster]

   2. To utter with breaks and interruption, in the manner of a
      person half suffocated. [R.]
      [1913 Webster]

            Throttle their practiced accent in their fears.
                                                  --Shak.
      [1913 Webster]

   3. To shut off, or reduce flow of, as steam to an engine.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Throttle \Throt"tle\, v. i.
   1. To have the throat obstructed so as to be in danger of
      suffocation; to choke; to suffocate.
      [1913 Webster]

   2. To breathe hard, as when nearly suffocated.
      [1913 Webster]

WordNet (r) 3.0 (2006):

throttle
    n 1: a valve that regulates the supply of fuel to the engine
         [syn: accelerator, throttle, throttle valve]
    2: a pedal that controls the throttle valve; "he stepped on the
       gas" [syn: accelerator, accelerator pedal, gas pedal,
       gas, throttle, gun]
    v 1: place limits on (extent or access); "restrict the use of
         this parking lot"; "limit the time you can spend with your
         friends" [syn: restrict, restrain, trammel, limit,
         bound, confine, throttle]
    2: kill by squeezing the throat of so as to cut off the air; "he
       tried to strangle his opponent"; "A man in Boston has been
       strangling several dozen prostitutes" [syn: strangle,
       strangulate, throttle]
    3: reduce the air supply; "choke a carburetor" [syn: choke,
       throttle]

Moby Thesaurus II by Grady Ward, 1.0:

110 Moby Thesaurus words for "throttle":
   abduct, arrest, asphyxiate, backpedal, backwater, bottle up, brake,
   burke, carry off, censor, check, choke, choke off, clamp down on,
   clip the wings, cork, cork up, crack down on, crush, curb,
   damp down, decelerate, deflate, delay, detain, disarm, draw rein,
   drown, dumbfound, ease off, ease up, enchain, extinguish, gag,
   garrote, hamstring, handcuff, hobble, hog-tie, hold back,
   hold down, hold in check, hold up, hush, hush-hush, impede,
   jump on, keep back, keep down, keep under, kidnap, kill, knock out,
   let down, let up, lose ground, lose momentum, lose speed, manacle,
   moderate, muffle, muzzle, obstruct, paralyze, pour water on,
   prostrate, put down, put to silence, quash, quell, quench, quiet,
   quieten, reef, rein in, relax, repress, retard, set back, shanghai,
   shush, shut down on, silence, sit down on, sit on, slack off,
   slack up, slacken, slow, slow down, slow up, smash, smother,
   soft-pedal, squash, squelch, stanch, stay, stifle, still,
   stop the breath, strangle, strike dumb, stultify, subdue,
   suffocate, suppress, take in sail, throttle down, truss up