The Collaborative International Dictionary of English v.0.48:

torture \tor"ture\, v. t. [imp. & p. p. tortured
   (t[^o]r"t[-u]rd; 135); p. pr. & vb. n. tTorturing.] [Cf. F.
   Torturer. ]
   1. To put to torture; to pain extremely; to harass; to vex.
      [1913 Webster]

   2. To punish with torture; to put to the rack; as, to torture
      an accused person. --Shak.
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   3. To wrest from the proper meaning; to distort. --Jar.
      Taylor.
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   4. To keep on the stretch, as a bow. [Obs.]
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            The bow tortureth the string.         --Bacon.
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The Collaborative International Dictionary of English v.0.48:

Torture \Tor"ture\ (t[^o]r"t[-u]r; 135), n. [F., fr. L. tortura,
   fr. torquere, tortum, to twist, rack, torture; probably akin
   to Gr. tre`pein to turn, G. drechseln to turn on a lathe, and
   perhaps to E. queer. Cf. Contort, Distort, Extort,
   Retort, Tart, n., Torch, Torment, Tortion, Tort,
   Trope.]
   1. Extreme pain; anguish of body or mind; pang; agony;
      torment; as, torture of mind. --Shak.
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            Ghastly spasm or racking torture.     --Milton.
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   2. Especially, severe pain inflicted judicially, either as
      punishment for a crime, or for the purpose of extorting a
      confession from an accused person, as by water or fire, by
      the boot or thumbkin, or by the rack or wheel.
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   3. The act or process of torturing.
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            Torture, which had always been deciared illegal, and
            which had recently been declared illegal even by the
            servile judges of that age, was inflicted for the
            last time in England in the month of May, 1640.
                                                  --Macaulay.
      [1913 Webster]

WordNet (r) 3.0 (2006):

torture
    n 1: extreme mental distress [syn: anguish, torment,
         torture]
    2: unbearable physical pain [syn: torture, torment]
    3: intense feelings of suffering; acute mental or physical pain;
       "an agony of doubt"; "the torments of the damned" [syn:
       agony, torment, torture]
    4: the act of distorting something so it seems to mean something
       it was not intended to mean [syn: distortion,
       overrefinement, straining, torture, twisting]
    5: the deliberate, systematic, or wanton infliction of physical
       or mental suffering by one or more persons in an attempt to
       force another person to yield information or to make a
       confession or for any other reason; "it required unnatural
       torturing to extract a confession" [syn: torture,
       torturing]
    v 1: torment emotionally or mentally [syn: torment, torture,
         excruciate, rack]
    2: subject to torture; "The sinners will be tormented in Hell,
       according to the Bible" [syn: torture, excruciate,
       torment]

Moby Thesaurus II by Grady Ward, 1.0:

206 Moby Thesaurus words for "torture":
   Procrustean bed, abuse, afflict, aggrieve, agonize, agonizingness,
   agony, ail, anguish, atrocious pain, bed of Procrustes, befoul,
   bewitch, bias, bite, blight, bloody, boot, burn, chafe, claw,
   clawing, color, condemn, confinement, contort, convulse, corrupt,
   cruciation, crucifixion, crucify, curse, cut, damage, defile,
   deprave, desolate, desolateness, desolation, despoil, destroy,
   disadvantage, dismember, dismemberment, disserve, distort,
   distress, do a mischief, do evil, do ill, do wrong, do wrong by,
   doom, draw and quarter, envenom, estrapade, excruciate,
   excruciatingness, excruciation, fester, fret, gall, galleys,
   garble, get into trouble, get one wrong, get wrong, give pain,
   gloss, gnaw, grate, grill, grind, gripe, harass, hard labor, harm,
   harrow, heartbreak, heartsickness, hell, hell upon earth, hex,
   holocaust, horror, hurt, impair, impale, impalement, imprisonment,
   incarceration, infect, inflame, inflict pain, injure, iron heel,
   irritate, jailing, jinx, keelhaul, keelhauling, kill by inches,
   lacerate, laceration, lancinate, lancination, macerate, maim,
   maltreat, mangle, martyr, martyrdom, martyrization, martyrize,
   menace, misapply, misapprehend, miscite, misconceive, misconstrue,
   misdeem, misdirect, misexplain, misexplicate, misexpound,
   misinterpret, misjudge, misquote, misread, misrender, misrepresent,
   misshape, mistake, mistranslate, mistreat, misunderstand, misuse,
   molest, mutilate, nightmare, nip, oppress, outrage, pain, passion,
   penal servitude, persecute, persecution, pervert, picket,
   picketing, pierce, pinch, play havoc with, play hob with, poison,
   pollute, prejudice, prick, prolong the agony, punish, purgatory,
   put to torture, rack, railriding, rankle, rasp, rip, rock pile,
   rub, savage, scarify, scarpines, scathe, screw, slant, smite,
   squeeze, stab, sting, strain, strain the sense, strappado, taint,
   tar and feather, tar-and-feathering, the gantlet, threaten,
   thumbscrew, torment, tormentingness, torturousness, try, tweak,
   twist, twist the words, varnish, violate, warp, wheel, wind, wound,
   wreak havoc on, wrench, wring, wrong



Bouvier's Law Dictionary, Revised 6th Ed (1856):

TORTURE, punishments. A punishment inflicted in some countries on supposed
criminals to induce them to confess their crimes, and to reveal their
associates.
     2. This absurd and tyrannical practice never was in use in the United
States; for no man is bound to accuse himself. An attempt to torture a
person accused of crime, in order to extort a confession, is an indictable
offence. 2 Tyler, 380. Vide Question.