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A system containing any combination of computers, computer terminals, printers, audio or visual display devices, or telephones interconnected by telecommunications equipment or cables: used to transmit or receive information. (Random House Unabridged Dictionary, 2d ed)

The extension of a company's intranet outonto the Internet, e.g. to allow selected customers,suppliers and mobile workers to access the company's privatedata and applications via the World-Wide Web. This is incontrast to, and usually in addition to, the company's publicwebsite which is accessible to everyone. The differencecan be somewhat blurred but generally an extranet impliesreal-time access through a firewall of some kind.Such facilities require very careful attention to security butare becoming an increasingly important means of deliveringservices and communicating efficiently.[Did Marc Andreessen invent the term in September 1996?]