( a. )
Acting as an instrument; serving as a means; contributing to promote; conductive; helpful; serviceable; as, he was instrumental in conducting the business.
( a. )
Acting as an instrument; serving as a means; contributing to promote; conductive; helpful; serviceable; as, he was instrumental in conducting the business.
Webster's Revised Unabridged English Dictionary. Пересмотренный полный словарь английского языка Webster. 2012