Instrument

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.

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

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.

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

To perform upon an instrument; to prepare for an instrument; as, a sonata instrumented for orchestra.

(law) a document that states some contractual relationship or grants some right

the semantic role of the entity (usually inanimate) that the agent uses to perform an action or start a process

the means whereby some act is accomplished; "my greed was the instrument of my destruction"; "science has given us new tools to fight disease"

equip with instruments for measuring, recording, or controlling