coprocessor

/ ˌkəʊˈprəʊsɛsə /

noun

1. computing a microprocessor circuit that operates alongside and supplements the capabilities of the main processor, providing, for example, high-speed arithmetic

coprocessor

/ kō′prŏs′ĕs-ər /

1. A microprocessor distinct from the central processing unit. A coprocessor performs specialized functions that the central processing unit cannot perform or cannot perform as well and as quickly.