Channel

1. A connection between initiating and terminating nodes of a circuit.
2. A single path provided by a transmission medium via either
   1. physical separation, such as by multipair cable or
   2. electrical separation, such as by frequency- or time-division multiplexing.
3. A path for conveying electrical or electromagnetic signals, usually distinguished from other parallel paths.
4. Used in conjunction with a predetermined letter, number, or codeword to reference a specific radio frequency.
5. The portion of a storage medium, such as a track or a band, that is accessible to a given reading or writing station or head.
6. In a communications system, the part that connects a data source to a data sink.

In physical geography, a channel is the physical confine of a river or slough, consisting of a bed and banks. See Stream bed.

A channel is also the natural or man-made deeper course through a reef, bar, bay, or any shallow body of water; also the navigable part of a river. See also: Ship channel.

The term channel is another word for strait, which is a relatively narrow body of water that connects two larger bodies of water. In this nautical context, the terms strait, channel, sound, and passage are synonymous and usually interchangeable. For example, in an archipelago, the water between islands is typically called a channel or passage. The English Channel is the strait between England and France.