Part or all of this entry has been imported from the 1913 edition of Webster’s Dictionary, which is now free of copyright and hence in the public domain. The imported definitions may be significantly out of date, and any more recent senses may be completely missing.
From Middle English, from Medieval Latin instrumentalis, from instruere (“to build into, set up, construct, furnish, hence "to train"”), from in- (“on”) + struere (“to put together, arrange, pile up, build, construct”), from Proto-Indo-European *strew- (“to spread, to strew”).
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- Acting as an instrument; serving as a means; contributing to promote; conductive; helpful; serviceable; essential or central.
- He was instrumental in conducting the business.
- (music) Pertaining to, made by, or prepared for, an instrument, especially a musical instrument.
- instrumental music
- (grammar) Applied to a case expressing means or agency, generally indicated in English by by or with with the objective.
- the instrumental case.
Coordinate terms 
Derived terms 
- instrumental in Webster’s Revised Unabridged Dictionary, G. & C. Merriam, 1913
- instrumental in The Century Dictionary, The Century Co., New York, 1911
instrumental m (plural instrumentaux)
See also 
From French instrumental.
instrumental (not comparable)
ȉnstrumentāl m (Cyrillic spelling и̏нструмента̄л)
instrumental m and f (plural instrumentales)