Meaning of instrument

in•stru•ment

1. a mechanical tool or implement, esp. one used for delicate or precision work: surgical instruments.
2. a contrivance or apparatus for producing musical sounds: a stringed instrument.
3. a means by which something is effected or done; agency: an instrument of government.
4. a device for measuring the present value of a quantity under observation.
5. a mechanical or electronic measuring device, esp. one used in navigation: landing a plane by instruments.
6. a formal legal document, as a draft or bond: negotiable instruments.
7. a person used by another merely as a means to some private end; tool or dupe.

1. to equip with instruments, as a machine or manufacturing process: to instrument a space vehicle.
2. to arrange a composition for musical instruments; orchestrate.