The instrument detected an increase in radioactivity.
noun A tool, implement used for manipulation or measurement.
The dentist set down his tray of instruments.
noun Ellipsis of flight instrument.
Flight within clouds must be made by reference to your instruments.
noun A legal document, such as a contract, deed, trust, mortgage, power, indenture, or will, or any of a class of negotiable ones (which can be exchanged for value or money).
A bond indenture is the instrument that gives a bond its value.
noun A person used as a mere tool for achieving a goal.