• IPA: /ɪnstɹəˈmɛntəl/, /ɪnstɹʊˈmɛntəl/

instrumental

1. essential or central; of great importance or relevance.

   He was instrumental in conducting the business.

   • c. 1599–1602, William Shakespeare, “The Tragedie of Hamlet, Prince of Denmarke”, in Mr. William Shakespeares Comedies, Histories, & Tragedies: Published According to the True Originall Copies (First Folio), London: Printed by Isaac Iaggard, and Ed[ward] Blount, published 1623, OCLC 606515358 ↗, [Act I, scene ii]:

     The head is not more native to the heart, The hand more instrumental to the mouth

   • 2012, Christoper Zara, Tortured Artists: From Picasso and Monroe to Warhol and Winehouse, the Twisted Secrets of the World's Most Creative Minds, part 1, chapter 2, gbooks :

     Few songwriters have been as instrumental in creating the mold for American music.

2. (music) Pertaining to, made by, or prepared for, an instrument, especially a musical instrument (rather than the human voice).

   instrumental music

   An instrumental part

   • 1848, Thomas Babington Macaulay, The History of England from the Accession of James the Second

     He defended the use of instrumental music in public worship.

   • c. 1700, John Dryden, Cymon and Iphigenia

     Sweet voices mix'd with instrumental sounds.

3. (grammar) Applied to a case expressing means or agency, generally indicated in English by by or with with the objective.

   the instrumental case

• noninstrumental

• German: dienlich, förderlich, entscheidend, hilfreich

• French: instrumental
• German: instrumental, instrumentell
• Portuguese: instrumental
• Spanish: instrumental

• French: instrumental
• German: Instrumentalis
• Portuguese: instrumental
• Russian: твори́тельный
• Spanish: instrumental

instrumental (plural instrumentals)

1. (grammar) The instrumental case.
2. (music) A composition written or performed without lyrics, sometimes using a lead instrument to replace vocals.
   • 1977, Stereo Review (volume 38, page 70)

     I recommend this album in the face of the fact that five of the eleven songs are the purest filler, dull instrumentals with a harmonica rifling over an indifferent rhythm section. The rest is magnificent […]

3. (plural only, music) The backing track of a song. The audio of a song without the vocal track.

• French: instrumental
• Portuguese: instrumental