The Collaborative International Dictionary of English v.0.48:

Stop \Stop\, v. t. [imp. & p. p. Stopped; p. pr. & vb. n.
   Stopping.] [OE. stoppen, AS. stoppian (in comp.); akin to
   LG. & D. stoppen, G. stopfen, Icel. stoppa, Sw. stoppa, Dan.
   stoppe; all probably fr. LL. stopare, stupare, fr. L. stuppa
   the coarse part of flax, tow, oakum. Cf. Estop, Stuff,
   Stupe a fomentation.]
   1. To close, as an aperture, by filling or by obstructing;
      as, to stop the ears; hence, to stanch, as a wound.
      --Shak.
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   2. To obstruct; to render impassable; as, to stop a way,
      road, or passage.
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   3. To arrest the progress of; to hinder; to impede; to shut
      in; as, to stop a traveler; to stop the course of a
      stream, or a flow of blood.
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   4. To hinder from acting or moving; to prevent the effect or
      efficiency of; to cause to cease; to repress; to restrain;
      to suppress; to interrupt; to suspend; as, to stop the
      execution of a decree, the progress of vice, the
      approaches of old age or infirmity.
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            Whose disposition all the world well knows
            Will not be rubbed nor stopped.       --Shak.
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   5. (Mus.) To regulate the sounds of, as musical strings, by
      pressing them against the finger board with the finger, or
      by shortening in any way the vibrating part.
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   6. To point, as a composition; to punctuate. [R.]
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            If his sentences were properly stopped. --Landor.
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   7. (Naut.) To make fast; to stopper.
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   Syn: To obstruct; hinder; impede; repress; suppress;
        restrain; discontinue; delay; interrupt.
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   To stop off (Founding), to fill (a part of a mold) with
      sand, where a part of the cavity left by the pattern is
      not wanted for the casting.

   To stop the mouth. See under Mouth.
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The Collaborative International Dictionary of English v.0.48:

Stop \Stop\, n.
   1. The act of stopping, or the state of being stopped;
      hindrance of progress or of action; cessation; repression;
      interruption; check; obstruction.
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            It is doubtful . . . whether it contributed anything
            to the stop of the infection.         --De Foe.
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            Occult qualities put a stop to the improvement of
            natural philosophy.                   --Sir I.
                                                  Newton.
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            It is a great step toward the mastery of our desires
            to give this stop to them.            --Locke.
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   2. That which stops, impedes, or obstructs; as obstacle; an
      impediment; an obstruction.
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            A fatal stop traversed their headlong course.
                                                  --Daniel.
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            So melancholy a prospect should inspire us with zeal
            to oppose some stop to the rising torrent. --Rogers.
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   3. (Mach.) A device, or piece, as a pin, block, pawl, etc.,
      for arresting or limiting motion, or for determining the
      position to which another part shall be brought.
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   4. (Mus.)
      (a) The closing of an aperture in the air passage, or
          pressure of the finger upon the string, of an
          instrument of music, so as to modify the tone; hence,
          any contrivance by which the sounds of a musical
          instrument are regulated.
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                The organ sound a time survives the stop.
                                                  --Daniel.
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      (b) In the organ, one of the knobs or handles at each side
          of the organist, by which he can draw on or shut off
          any register or row of pipes; the register itself; as,
          the vox humana stop.
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   5. (Arch.) A member, plain or molded, formed of a separate
      piece and fixed to a jamb, against which a door or window
      shuts. This takes the place, or answers the purpose, of a
      rebate. Also, a pin or block to prevent a drawer from
      sliding too far.
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   6. A point or mark in writing or printing intended to
      distinguish the sentences, parts of a sentence, or
      clauses; a mark of punctuation. See Punctuation.
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   7. (Opt.) The diaphragm used in optical instruments to cut
      off the marginal portions of a beam of light passing
      through lenses.
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   8. (Zool.) The depression in the face of a dog between the
      skull and the nasal bones. It is conspicuous in the
      bulldog, pug, and some other breeds.
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   9. (Phonetics) Some part of the articulating organs, as the
      lips, or the tongue and palate, closed
      (a) so as to cut off the passage of breath or voice
          through the mouth and the nose (distinguished as a
          lip-stop, or a front-stop, etc., as in p, t, d, etc.),
          or
      (b) so as to obstruct, but not entirely cut off, the
          passage, as in l, n, etc.; also, any of the consonants
          so formed. --H. Sweet.
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   Stop bead (Arch.), the molding screwed to the inner side of
      a window frame, on the face of the pulley stile,
      completing the groove in which the inner sash is to slide.


   Stop motion (Mach.), an automatic device for arresting the
      motion of a machine, as when a certain operation is
      completed, or when an imperfection occurs in its
      performance or product, or in the material which is
      supplied to it, etc.

   Stop plank, one of a set of planks employed to form a sort
      of dam in some hydraulic works.

   Stop valve, a valve that can be closed or opened at will,
      as by hand, for preventing or regulating flow, as of a
      liquid in a pipe; -- in distinction from a valve which is
      operated by the action of the fluid it restrains.

   Stop watch, a watch the hands of which can be stopped in
      order to tell exactly the time that has passed, as in
      timing a race. See Independent seconds watch, under
      Independent, a.
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   Syn: Cessation; check; obstruction; obstacle; hindrance;
        impediment; interruption.
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The Collaborative International Dictionary of English v.0.48:

Stop \Stop\, v. i.
   1. To cease to go on; to halt, or stand still; to come to a
      stop.
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            He bites his lip, and starts;
            Stops on a sudden, looks upon the ground;
            Then lays his finger on his temple: strait
            Springs out into fast gait; then stops again.
                                                  --Shak.
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   2. To cease from any motion, or course of action.
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            Stop, while ye may, suspend your mad career!
                                                  --Cowper.
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   3. To spend a short time; to reside temporarily; to stay; to
      tarry; as, to stop with a friend. [Colloq.]
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            By stopping at home till the money was gone. --R. D.
                                                  Blackmore.
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   To stop over, to stop at a station or airport beyond the
      time of the departure of the train or airplane on which
      one came, with the purpose of continuing one's journey on
      a subsequent train or airplane; to break one's journey.
      See stopover, n.
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WordNet (r) 3.0 (2006):

stop
    n 1: the event of something ending; "it came to a stop at the
         bottom of the hill" [syn: stop, halt]
    2: the act of stopping something; "the third baseman made some
       remarkable stops"; "his stoppage of the flow resulted in a
       flood" [syn: stop, stoppage]
    3: a brief stay in the course of a journey; "they made a
       stopover to visit their friends" [syn: stop, stopover,
       layover]
    4: the state of inactivity following an interruption; "the
       negotiations were in arrest"; "held them in check"; "during
       the halt he got some lunch"; "the momentary stay enabled him
       to escape the blow"; "he spent the entire stop in his seat"
       [syn: arrest, check, halt, hitch, stay, stop,
       stoppage]
    5: a spot where something halts or pauses; "his next stop is
       Atlanta"
    6: a consonant produced by stopping the flow of air at some
       point and suddenly releasing it; "his stop consonants are too
       aspirated" [syn: stop consonant, stop, occlusive,
       plosive consonant, plosive speech sound, plosive] [ant:
       continuant, continuant consonant]
    7: a punctuation mark (.) placed at the end of a declarative
       sentence to indicate a full stop or after abbreviations; "in
       England they call a period a stop" [syn: period, point,
       full stop, stop, full point]
    8: (music) a knob on an organ that is pulled to change the sound
       quality from the organ pipes; "the organist pulled out all
       the stops"
    9: a mechanical device in a camera that controls size of
       aperture of the lens; "the new cameras adjust the diaphragm
       automatically" [syn: diaphragm, stop]
    10: a restraint that checks the motion of something; "he used a
        book as a stop to hold the door open" [syn: catch, stop]
    11: an obstruction in a pipe or tube; "we had to call a plumber
        to clear out the blockage in the drainpipe" [syn:
        blockage, block, closure, occlusion, stop,
        stoppage]
    v 1: come to a halt, stop moving; "the car stopped"; "She
         stopped in front of a store window" [syn: stop, halt]
         [ant: get going, go, start]
    2: put an end to a state or an activity; "Quit teasing your
       little brother" [syn: discontinue, stop, cease, give
       up, quit, lay off] [ant: bear on, carry on,
       continue, preserve, uphold]
    3: stop from happening or developing; "Block his election";
       "Halt the process" [syn: stop, halt, block, kibosh]
    4: interrupt a trip; "we stopped at Aunt Mary's house"; "they
       stopped for three days in Florence" [syn: stop, stop
       over]
    5: cause to stop; "stop a car"; "stop the thief" [ant: start,
       start up]
    6: prevent completion; "stop the project"; "break off the
       negotiations" [syn: break, break off, discontinue,
       stop]
    7: hold back, as of a danger or an enemy; check the expansion or
       influence of; "Arrest the downward trend"; "Check the growth
       of communism in South East Asia"; "Contain the rebel
       movement"; "Turn back the tide of communism" [syn: check,
       turn back, arrest, stop, contain, hold back]
    8: seize on its way; "The fighter plane was ordered to intercept
       an aircraft that had entered the country's airspace" [syn:
       intercept, stop]
    9: have an end, in a temporal, spatial, or quantitative sense;
       either spatial or metaphorical; "the bronchioles terminate in
       a capillary bed"; "Your rights stop where you infringe upon
       the rights of other"; "My property ends by the bushes"; "The
       symphony ends in a pianissimo" [syn: end, stop, finish,
       terminate, cease] [ant: begin, start]
    10: render unsuitable for passage; "block the way"; "barricade
        the streets"; "stop the busy road" [syn: barricade,
        block, blockade, stop, block off, block up, bar]
    11: stop and wait, as if awaiting further instructions or
        developments; "Hold on a moment!" [syn: hold on, stop]

Moby Thesaurus II by Grady Ward, 1.0:

538 Moby Thesaurus words for "stop":
   English horn, abandon, abjure, abort, afterthought, allophone,
   alveolar, anchorage, apico-alveolar, apico-dental, arrest,
   arrestation, articulation, aspiration, assimilation, awe, baffle,
   ban, bar, barricade, barrier, bassoon, bearing rein, beat off,
   belay, bell, bilabial, bind, bit, blank wall, blind alley,
   blind gut, block, block flute, block up, blockade, blockage,
   blocking, bombard, bottleneck, boundary, bourdon, bourn, box,
   brake, break, break of, break off, break the habit, bring to,
   bring up, bring up short, bung, bureaucratic delay, cacuminal,
   caesura, call on, call upon, calm, calm down, cancel, caulk, cease,
   cease fire, cecum, cello, cerebral, cessation, chain, check,
   check valve, checkmate, checkrein, chink, chock, choke, choke off,
   choke up, choking, choking off, claribel, clarinet, clarion, clog,
   clog up, close, close off, close up, closing, closing up, cock,
   colon, come off, come up short, comma, concert flute, conclude,
   conclusion, confine, congest, congestion, consonant, constipate,
   constipation, continuant, cork, corner, cornet, cornopean,
   costiveness, counter, countercheck, cover, cromorna, cul-de-sac,
   curb, curb bit, cure, cushion, cut it out, cut off, cut out,
   cut short, cutoff, cymbel, dam, dam up, damp, dampen, damper,
   daunt, dead end, dead set, dead stand, dead stop, dead-end street,
   deaden, deadlock, deafen, debarment, delay, delayage,
   delayed reaction, dental, depot, desist, desist from, desistance,
   destination, detain, detention, deter, determent, determine,
   deterrence, diacritical mark, diapason, die down, diphthong,
   disaccustom, discontinuance, discontinue, discourage,
   discouragement, dishearten, dissimilation, disuse, doorstop,
   double take, drag, drag sail, dragging, draw rein, draw up,
   drift anchor, drift sail, drive back, drogue, drop, drop in,
   drop it, dulciana, dull, dwindle, dying down, ebb, ebbing,
   embolism, embolus, end, end stop, endgame, ending,
   epenthetic vowel, estoppel, explosive, extremity, faucet, faze,
   fence, fend, fend off, fetch up, fetter, fill, fill up,
   final whistle, finish, finish up, flute stop, forbiddance,
   foreclosure, forestalling, forswear, foul, foundation stop,
   fourniture, freeze, full stop, gamba, gedeckt, gemshorn, give over,
   give up, glide, glottal, glottalization, goal, gorge,
   grinding halt, gun, guttural, halt, hang fire, hang-up, harbor,
   harmonic flute, have done with, haven, hinder, hindrance, hold,
   hold at bay, hold back, hold off, hold up, holdback, holdup, hole,
   hybrid stop, impasse, impede, impediment, infarct, infarction,
   interim, interrupt, jam, jam up, juncture, keep at bay, keep back,
   keep off, kick, knock it off, koppel flute, labial, labialization,
   labiodental, labiovelar, lag, lagging, larigot, laryngeal,
   last stop, lateral, lay off, lay over, layover, leave off, let go,
   lid, lingual, liquid, lock, lockout, lodge, logjam, look in, lull,
   make late, manner of articulation, martingale, melodia, mixture,
   modification, molder, monophthong, moratorium, morphophoneme,
   muffle, mutation stop, mute, nasal, nazard, nol-pros,
   not pursue with, oboe, obstacle, obstipate, obstipation, obstruct,
   obstruction, obviation, occlusive, octave, organ stop, overawe,
   pacify, pack, pack in, palatal, paperasserie, parasitic vowel,
   parry, pause, pay a visit, peak, peg, pelham, period, perorate,
   peter out, pharyngeal, pharyngealization, phone, phoneme, piccolo,
   pin, plein jeu, plosive, plug, plug up, point, port, posaune,
   preclusion, prevent, prevention, principal, prohibition,
   prothetic vowel, pull up, punctuation, punctuation marks,
   push back, put back, put behind one, put paid to, put up, quiesce,
   quiet, quieten, quint, quintaten, quit, rank, ranket, rebuff,
   red tape, red-tapeism, red-tapery, reed stop, reference,
   reference mark, refrain, refrain from, register, relinquish,
   remora, renounce, repel, reprieve, repulse, resign, resolve,
   respite, rest, restrain, retard, retardance, retardation,
   retroflex, roadblock, rohr flute, run in, scotch, scrap, scratch,
   scrub, sea anchor, sea cock, sealing off, see, segmental phoneme,
   semicolon, semivowel, sesquialtera, shackle, shake, shawm,
   sit-down strike, slacken, slow, slow down, slow-up, slowdown,
   slowness, snaffle, soft-pedal, soften, sojourn, sojournment,
   sonant, sonority, soothe, speech sound, spigot, spike, spile,
   spill, spitz flute, spoke, stage, stalemate, stall, stanch, stand,
   standoff, standstill, station, staunch, stave off, stay,
   stay of execution, stay over, stayover, stem, stem the tide,
   stench, stick, stillstand, stop by, stop cold, stop dead, stop off,
   stop over, stop short, stop up, stop-off, stopgap, stopover,
   stoppage, stopped diapason, stopped flute, stopper, stopping,
   stopping place, stopple, strangulation, strike, string diapason,
   string stop, stuff, stuff up, stymie, subdue, subside, subsidence,
   suppress, surd, suspension, swear off, syllabic nucleus,
   syllabic peak, syllable, take a break, take the pledge, tap, tarry,
   terminal, terminal point, terminate, termination, terminus,
   throw off, thwart, tie-up, tierce, time lag, tittle, tone down,
   trammel, tranquilize, transition sound, tremolo, triphthong,
   trombone, trumpet, turn aside, twelfth, unda maris, valve, velar,
   vibrato, viola, visit, vocable, vocalic, vocoid, voice,
   voiced sound, voiceless sound, voicing, voix celeste, vowel,
   vox angelica, vox humana, wait, waive, walkout, wall, wane, waning,
   ward off, wean, wind up, work stoppage