What is Instrument?

Instrument definition and meaning on Dictionary terms:
a mechanical tool or implement, especially one used for delicate or precision work: surgical instruments.
a contrivance or apparatus for producing musical sounds: a stringed instrument.
a means by which something is effected or done; agency: an instrument of government.
a device for measuring the present value of a quantity under observation.

a mechanical or electronic measuring device, especially one used in navigation: landing a plane by instruments.
a formal legal document, as a draft or bond: negotiable instruments.
a person used by another merely as a means to some private end; tool or dupe.

verb (used with object)
to equip with instruments, as a machine or manufacturing process: to instrument a space vehicle.
to arrange a composition for musical instruments; orchestrate.