1. The application or use of instruments.
2. Music.
   1. The study and practice of arranging music for instruments.
   2. The arrangement or orchestration resulting from such practice.
   3. A list of instruments used in an orchestration.
3. 1. The study, development, and manufacture of instruments, as for scientific or industrial use.
   2. Instruments for a specific purpose.
4. Instrumentality.

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.