Acting as an instrument; serving as a means; contributing to promote; conductive; helpful; serviceable; as, he was instrumental in conducting the business.
Pertaining to, made by, or prepared for, an instrument, esp. a musical instrument; as, instrumental music, distinguished from vocal music.
Applied to a case expressing means or agency; as, the instrumental case. This is found in Sanskrit as a separate case, but in Greek it was merged into the dative, and in Latin into the ablative. In Old English it was a separate case, but has disappeared, leaving only a few anomalous forms.
Egypt has been a partner of the United States over the last 30 years, has been instrumental in keeping the peace in the Middle East between Egypt and Israel, which is a critical accomplishment that has meant so much to so many people. Hillary Clinton
In chess one cannot control everything. Sometimes a game takes an unexpected turn, in which beauty begins to emerge. Both players are always instrumental in this. Vladimir Kramnik
And I loved Fats Waller. I love his instrumental abilities, his vocal abilities and his sense of humor. Paul McCartney
I have been instrumental in banning bottled water on the set. It hasn't gone that well with the crew... so I replaced it with tequila. Hugh Laurie
I realised a long time ago that instrumental music speaks a lot more clearly than English, Spanish, Yiddish, Swahili, any other language. Pure melody goes outside time. Carlos Santana