1. (n.) That by means of which any work is performed, or result is effected; a tool; a utensil; an implement; as, the instruments of a mechanic; astronomical instruments.

2. (n.) A contrivance or implement, by which musical sounds are produced; as, a musical instrument.

3. (n.) 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.

4. (n.) One who, or that which, is made a means, or is caused to serve a purpose; a medium, means, or agent.

5. (v. t.) To perform upon an instrument; to prepare for an instrument; as, a sonata instrumented for orchestra.

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