Instrumental

[in-struh-men-tl] /ˌɪn strəˈmɛn tl/

adjective
1.
serving or acting as an instrument or means; useful; helpful.
2.
performed on or written for a musical instrument or instruments:
instrumental music.
3.
of or relating to an instrument or tool.
4.
Grammar.

noun
5.
Grammar.

6.
a musical composition played by an instrument or a group of instruments.
Compare (def 8).
/ˌɪnstrəˈmɛntəl/
adjective
1.
serving as a means or influence; helpful
2.
of, relating to, or characterized by an instrument or instruments
3.
played by or composed for musical instruments
4.
(grammar) denoting a case of nouns, etc, in certain inflected languages, indicating the instrument used in performing an action, usually translated into English using the prepositions with or by means of
noun
5.
a piece of music composed for instruments rather than for voices
6.
(grammar)

adj.

late 14c., “of the nature of an instrument,” from Old French instrumental, from Medieval Latin instrumentalis, from Latin instrumentum (see instrument). Meaning “serviceable, useful” is from c.1600. Of music, c.1500; noun meaning “musical composition for instruments only” is attested by 1940. Related: Instrumentally; instrumentality.