The Collaborative International Dictionary of English v.0.48:

Instrument \In"stru*ment\, v. t.
   1. To perform upon an instrument; to prepare for an
      instrument; as, a sonata instrumented for orchestra.
      [1913 Webster]

   2. To furnish or equip with instruments; to attach
      instruments to; as, the fighter planes were heavily
      instrumented; the patient was instrumented to monitor him
      remotely.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Instrument \In"stru*ment\, n. [F. instrument, L. instrumentum.
   See Instruct.]
   [1913 Webster]
   1. That by means of which any work is performed, or result is
      effected; a tool; a utensil; an implement; a device; as,
      the instruments of a mechanic; astronomical instruments.
      [1913 Webster]

            All the lofty instruments of war.     --Shak.
      [1913 Webster]

   2. A contrivance or implement, by which musical sounds are
      produced; as, a musical instrument.
      [1913 Webster]

            Praise him with stringed instruments and organs.
                                                  --Ps. cl. 4.
      [1913 Webster]

            But signs when songs and instruments he hears.
                                                  --Dryden.
      [1913 Webster]

   3. (Law) A writing, as the means of giving formal expression
      to some act; a writing expressive of some act, contract,
      process, as a deed, contract, writ, etc. --Burrill.
      [1913 Webster]

   4. One who, or that which, is made a means, or is caused to
      serve a purpose; a medium, means, or agent; as, their army
      was primarily an instrument of oppression.
      [1913 Webster +PJC]

            Or useful serving man and instrument,
            To any sovereign state.               --Shak.
      [1913 Webster]

            The bold are but the instruments of the wise.
                                                  --Dryden.

   Syn: Tool; implement; utensil; machine; apparatus; channel;
        agent.
        [1913 Webster]

WordNet (r) 3.0 (2006):

instrument
    n 1: a device that requires skill for proper use
    2: the means whereby some act is accomplished; "my greed was the
       instrument of my destruction"; "science has given us new
       tools to fight disease" [syn: instrument, tool]
    3: a person used by another to gain an end [syn: instrument,
       pawn, cat's-paw]
    4: (law) a document that states some contractual relationship or
       grants some right [syn: legal document, legal instrument,
       official document, instrument]
    5: the semantic role of the entity (usually inanimate) that the
       agent uses to perform an action or start a process [syn:
       instrumental role, instrument]
    6: any of various devices or contrivances that can be used to
       produce musical tones or sounds [syn: musical instrument,
       instrument]
    v 1: equip with instruments for measuring, recording, or
         controlling
    2: write an instrumental score for [syn: instrument,
       instrumentate]
    3: address a legal document to

Moby Thesaurus II by Grady Ward, 1.0:

440 Moby Thesaurus words for "instrument":
   Bourdon tube, Charlie McCarthy, Danish balance, Federal,
   Gramophone, Gyropilot, Mach meter, Roman balance, Teletype,
   Weightometer, X-ray machine, absolute altimeter, accelerometer,
   adapt, aerial reconnaissance camera, aerometer, aeroscope, agency,
   agent, air log, alloy balance, altigraph, altimeter, amanuensis,
   ammeter, analytical balance, ancilla, anemograph, anemometer,
   anemoscope, aneroid, antler, apparatus, apple-polisher, appliance,
   arrange, aspirator, ass-licker, assay balance, autograph,
   automatic pilot, autosyn, awl, backslapper, baggage agent, balance,
   balance of precision, barb, barbed wire, barblet, barbule,
   barbwire, barometer, barrel scale, beam, bedpan, blank, bodkin,
   bombing locator, bombsight, bootlick, bootlicker, bradawl,
   brown-nose, brownie, bullion balance, business agent, calorimeter,
   caltrop, card compass, carpet tack, cash register, catalyst,
   catheter, channel, cheval-de-frise, chirograph, chromatoscope,
   chronograph, chronometer, chuck, claim agent, clamp, clasp,
   clawback, clerk, clinch, clinical thermometer, clip, cockspur,
   commercial agent, commission agent, compact, compass, compose,
   consignee, contract, contraption, contrivance, control rod,
   counter scale, courtier, cramp, creature, cringer, customer agent,
   cylinder scale, device, diathermy machine, dibble,
   direction finder, docket, document, dog, dossier, drain,
   drum scale, dummy, dupe, electrocardiograph, electroencephalograph,
   electrograph, equipment, evaporimeter, facsimile telegraph, factor,
   fan scale, fawner, fed, federal agent, fid, file, fishhook,
   flatterer, flexure plate scale, flight recorder, flunky,
   footlicker, forceps, fork, form, freight agent, functionary,
   gadget, gaff, galvanometer, gauge, gauger, gear, general agent,
   gimcrack, gimlet, gimmick, gizmo, go-between, goad, goniometer,
   gosport, gosport tube, grab, grapnel, grapple, grappler,
   grappling iron, grip, groveler, gyrocompass, hand tool, handmaid,
   handmaiden, handshaker, harmonize, harpoon, hat pin, heat lamp,
   helot, hemostat, holdfast, holograph, hook, horn, hub dynamometer,
   hygrograph, hygrometer, hypo, hypodermic, hypodermic needle,
   hypsometer, icepick, implement, inclinometer, induction compass,
   instrumentality, instrumentate, instrumentation, insurance agent,
   interagent, intermediary, intermediate, intermedium, jackal, jaws,
   joy stick, kaleidoscope, kowtower, kymograph, lackey, lance,
   lancet, land agent, laser, law agent, led captain, legal document,
   legal instrument, legal paper, lever, lever scales, lickspit,
   lickspittle, literary agent, loan agent, long-arm balance, machine,
   machinery, magnetic compass, make an adaptation, manometer,
   marlinespike, mealymouth, mean, means, measure, measurer,
   mechanical device, mechanical heart, mechanism, mechanize,
   mediator, medium, melodize, meteorograph, meter, microfilm reader,
   micrometer, microscope, midwife, mill, minion, ministry, motorize,
   musicalize, nail, needle, news agent, nippers, octant, official,
   official document, optical altimeter, orchestrate, organ,
   oscillograph, otoscope, oxgoad, ozonometer, pact, pair of scales,
   paper, paper clip, papers, paraphernalia, parchment, pari-mutuel,
   pari-mutuel machine, parliamentary agent, passenger agent, pawn,
   peon, personal file, photometer, pike, pin, pincers, pitchfork,
   pitot-static tube, plate fulcrum scale, platform scale, plaything,
   pliers, pluviograph, pluviometer, pneumatograph, pneumatometer,
   potentiometer, power tool, precision balance, precision scale,
   precision tool, press agent, prime mover, prism, probe, prong,
   punch, puppet, purchasing agent, pus basin, put to music,
   pyrometer, quadrant, quill, radar, radio, radio compass,
   radio direction finder, radiogoniometer, range finder,
   rate-of-climb indicator, real estate agent, recording barometer,
   recording hygrometer, register, retool, robot pilot, roll, rowel,
   sales agent, scale, scales, scalpel, score, scrip, script, scroll,
   secretary, seismograph, seismoscope, serf, servant, set,
   set to music, sextant, sharpen, short-arm balance, skewer, slave,
   sound, sound recorder, spaniel, spearhead, special agent,
   spectrograph, spectrohelioscope, spectroscope, speculum,
   speed tool, spicule, spiculum, spike, spine, spiral balance,
   spirit level, spirometer, spit, splint, spur, staple, static tube,
   station agent, stereopticon, stethoscope, steward, sting, stooge,
   strike radar scanner, suck, sun compass, suture, swab, sycophant,
   syringe, tachometer, tack, tackle, tang, tape recorder,
   teletypewriter, telltale, theatrical agent, thermograph,
   thermometer, thermometrograph, thermostat, thingumabob,
   thingumajig, thingummy, throttle, thumbtack, ticker, ticket agent,
   timeserver, tine, toad, toady, tongs, tool, toy, transcribe,
   transit instrument, transpose, travel agent, trepan, trephine,
   truckler, tufthunter, turnstile, tweezers, utensil, variometer,
   vehicle, venturi tube, viewer, viscosimeter, vise, voting machine,
   walking delegate, way, weigh scales, weighbridge, weighing machine,
   weight voltameter, whatnot, wherewithal, wrench, writ, write,
   writing, yes-man, yoke



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

instrument

    To install devices or instructions into hardware
   or software to monitor the operation of a system or component.

   (1996-05-22)


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

INSTRUMENT, contracts. The writing which contains some agreement, and is so
called because it has been prepared as a memorial of what has taken place or
been agreed upon. The agreement and the instrument in which it is contained
are very different things, the latter being only evidence of the existence
of the former. The instrument or form of the contract may be valid, but the
contract itself may be void on account of fraud. Vide Ayl. Parerg. 305;
Dunl. Ad. Pr. 220.



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

INSTRUMENTA. This word is properly applied to designate that kind of
evidence, which consists of writings not under seal, as court rolls,
accounts, and the like. 3 Tho. Co. Litt. 487.