1. An assembly of computer hardware, software, firmware, or any combination of these, configured to accomplish specific information-handling operations, such as communication, computation, dissemination, processing, and storage of information.
2. In INFOSEC, any equipment or interconnected system or subsystems of equipment that is used in the automatic acquisition, storage, manipulation, management, movement, control, display, switching, interchange, transmission or reception of data and includes computer software, firmware, and hardware.
Note: Included are computers, word processing systems, networks, or other electronic information handling systems, and associated equipment.
Source: from Federal Standard 1037C and from the National Information Systems Security Glossary