1. (a.) Acting as an instrument; serving as a means; contributing to promote; conductive; helpful; serviceable; as, he was instrumental in conducting the business.
2. (a.) Pertaining to, made by, or prepared for, an instrument, esp. a musical instrument; as, instrumental music, distinguished from vocal music.
3. (a.) 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.
Thesaurus Entries
accessory, adjuvant, advantageous, agential, agentival, agentive, ancillary, assistant, assisting, auxiliary, beneficial, catalytic, concert, conducive, contributory, dramatico-musical, employable, facilitating, favoring, forwarding, fostering, handy, helpful, helping, important, intermediary, jazz, jazzy, mediating, mediatorial, ministerial, ministering, ministrant, nurtural, nutricial, of service, orchestral, promoting, rock, serviceable, serving, significant, subservient, subsidiary, supporting, supportive, swing, symphonic, syncopated, useful, utilitarian, valuable
