[in.stru.ment] n [ME, fr. L instrumentum, fr. instruere to arrange, instruct] (14c) 1: a device used to produce music
2. a: a means whereby something is achieved, performed, or furthered b: one used by another as a means or aid: dupe, tool
3: implement; esp: one designed for precision work
4: a formal legal document (as a deed, bond, or agreement)
5. a: a measuring device for determining the present value of a quantity under observation b: an electrical or mechanical device used in navigating an airplane; esp: such a device used as the sole means of navigating syn see implement
in.stru.ment vt (1752) 1: to address a legal instrument to
2: to score for musical performance: orchestrate
3: to equip with instruments esp. for measuring and recording data "an instrumented spacecraft"