Processor

A processor is the logic circuitry that responds to and processes the basic instructions that drive a computer.

The term processor has generally replaced the term central processing unit (CPU). The processor in a personal computer or embedded in small devices is often called a microprocessor.

It contains a small, high-speed memory used to store temporary result and certain control information

Made up of a number of register each having certain size and function. Usually the register have same size. Each register can hold one number, up to some maximum determined by it size.