What is the Difference Between "Transmission" and "Retransmission"?

Replaying music in another location

A transmission of a performance is one that is sent by any device or process (for example, radio, TV, cable, satellite, telephone) and received in a different place.

A retransmission is a further transmission of that performance to yet another place. An example is when a cable system retransmits the signal that it receives from a local television station to yet another location.