1. noun. A tool or device used for a particular purpose.
2. noun. A measuring device used to determine the present value or quantity under observation.
3. noun. A device that is used to produce or make music.
4. noun. One used by another to accomplish a purpose.
5. noun. An electrical or mechanical device used in navigating an airplane.
6. noun. A means whereby something is achieved, performed or furthered.
7. verb. To score for musical performance.