Parts or elements that make up a system or whole object and perform specific functions. For example, the major components of a car include: a chassis (holds everything on it); an engine (to convert energy to make a car move); a transmission (including controlling the speed and output from the engine and to rotate the wheels); a steering system (to control the direction of movement); a brake system (to slow down or stop); a fuel delivery system (to supply fuel to the cylinders); an exhaust system (to get rid of gases) and an electrical system (for operating wipers, air conditioning, etc.).

Similarly, the components of a computer system may be a central processing unit (chips that follow instructions to control other components and move data); memory chips and a hard disk (for storing data and instructions); a keyboard, a mouse, a camera and a microphone (to input instructions and data for the central processing unit); a screen, a printer and speakers (to output data); USB and ethernet cards (to communicate with other systems or components). Also see digital systems.

diagram showing components of an electronic system.