instrument
/ˈɪnstɹəmənt/
A device used to produce music.
The violinist was a master of her instrument.
A means or agency for achieving an effect.
A measuring or displaying device.
The instrument detected an increase in radioactivity.
A tool, implement used for manipulation or measurement.
The dentist set down his tray of instruments.
A legal document, such as a contract, deed, trust, mortgage, power, indenture, or will.
A bond indenture is the instrument that gives a bond its value.
A person used as a mere tool for achieving a goal.