/ ˈɪnstrəmənt; NAmE / noun
1.
a tool or device used for a particular task, especially for delicate or scientific work :
surgical / optical / precision, etc. instruments
instruments of torture
2.
= musical instrument :
Is he learning an instrument?
brass / stringed, etc. instruments
3.
a device used for measuring speed, distance, temperature, etc. in a vehicle or on a piece of machinery :
the flight instruments
the instrument panel
4.
instrument of / for sth ( formal ) something that is used by sb in order to achieve sth; a person or thing that makes sth happen :
The law is not the best instrument for dealing with family matters.
an instrument of change
5.
instrument of sb/sth ( formal ) a person who is used and controlled by sb/sth that is more powerful :
an instrument of fate
6.
( law ) a formal legal document
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WORD ORIGIN
Middle English : from Old French , or from Latin instrumentum equipment, implement, from the verb instruere construct, equip.