In communications, transmission is the act of transmitting electrical messages (and the associated phenonomena of radiant energy that pass through media).

In telecommunication, the term transmission has the following meanings:

1. The dispatching, for reception elsewhere, of a signal, message, or other form of information.

2. A synonym for transmission coefficient.

3. The propagation of a signal, message, or other form of information by any means, such as by telegraph, telephone, radio, television, or facsimile via any medium, such as wire, coaxial cable, microwave, optical fiber, or radio frequency.

4. In communications systems, a series of data units, such as blocks, messages, or frames.

5. The transfer of electrical power from one location to another via conductors.

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