Etymology

From Middle English instrument, from Old French instrument, from Latin īnstrūmentum (“an implement, tool”), suffix -mentum.

1. A device used to produce music. quotations ▼

   The violinist was a master of her instrument.

2. A means or agency for achieving an effect. quotations ▼
3. A measuring or displaying device.

   The instrument detected an increase in radioactivity.

4. A tool, implement used for manipulation or measurement.

   The dentist set down his tray of instruments.

   The scientist recorded the temperature with a thermometer but wished he had a more accurate instrument.

5. (law) 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.

   Negotiable instruments are the foundation of the debt markets.

6. (figuratively) A person used as a mere tool for achieving a goal.