instrumentaladj/ɪnstɹəˈmɛntəl/

• 1

  Essential or central; of great importance or relevance.

  • He was instrumental in conducting the business.
  • The head is not more native to the heart, The hand more instrumental to the mouth
• 2

  Serving as an instrument, medium, means, or agency.

  • Maxwell started back to his study, feeling that kind of satisfaction which a man feels when he has been even partly instrumental in finding an unemployed person a remunerative position.
• 3

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

  • instrumental music
  • an instrumental part
• 4

  grammarhuman-scienceslinguisticsOf or relating to a case expressing means or agency, generally corresponding to the English use of prepositions such as by, with, through, or by means of with the objective case.

  • the instrumental case

instrumentalnoun/ɪnstɹəˈmɛntəl/

• 1

  grammarhuman-scienceslinguisticsThe instrumental case.

• 2

  entertainmentlifestylemusicA composition written or performed without lyrics or singing, using a lead instrument to replace vocals.

  • 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

  entertainmentlifestylemusicA pause in the vocals of a song, usually occurring midway through, in which a musical instrument replaces the vocals.