Online means being connected to the Internet or another similar electronic network, like a bulletin board system. Some companies have "online" in their name, such as America Online. Although it sounds similar, online is not the same as on air. When one is online, one can receive and transmit information, whereas when one is on the air, one is broadcasting television or radio signals.

Some consider certain experiences while online to be taking place in a universe called cyberspace that is distinct from real life, the world of experience when offline. A variety of slang terminology has evolved to describe these cyberspacial experiences.

Online also refers to information stored in a computer, whether networked or not, as distinct from media such as paper that are not mechnically searchable.

External links

• NetLingo: dictionary of online terminology
• Tools to keep you online all the time
• The Epic Saga of The Well - The World's Most Influential Online Community, Wired Magazine

In telecommunication, the term on-line has the following meanings:

1. Pertaining to the operation of a functional unit when under the direct control of the system with which it is associated.

Note 1: On-line units are available for immediate use on demand by the system without human intervention.

Note 2: On-line units may not be independently operated.

2. Pertaining to equipment that is connected to a system, and is in operation.

Source: from Federal Standard 1037C and from MIL-STD-188

In electrical generation, power plants are said to be online when supplying electrical power to the electrical network.