Relaying is a process in which one streaming server rebroadcasts the audio stream from another streaming server. Typically this is used to distribute listeners across multiple streaming servers, however it can also be used for other purposes such as stream syndication.

Your streaming server can be configured as a relay (thereby rebroadcasting an audio stream being generated by another server), or it can be configured to allow relaying by other streaming servers (thereby allowing other servers to rebroadcast the audio stream being generated by your server.)