An instrument is a concrete or abstract tool intended for a purpose other than mechanical work, in particular a refined one.
Musical instruments are devices designed to produce music, frequently by plucking or striking a string or bell or drum surface, or by forcing air to resonate (see wind instruments).
... Law of Canada (http://www.constitutional-law.net/general.html) by Professor Joseph E. Magnet, University of Ottawa
Bibliography
Hogg, P. W., Constitutional law of ...