REPEATER

"Repeater" in the wireless world is a receiver and a transmitter, located a distance away from a main transmitter.  What a repeater does is to receive the signal from the main transmitter from one direction, and then to amplify it and "repeat" the same signal much stronger in another or continued direction.  In this case, a transmitted signal could have much more range than originally expected - since repeaters could continue to amplify and broadcast the signal at distances far away to get it back up to high power and therefore broadcast it much further.

For example, the original base stations for car telephone before cellular was invented might be in the central downtown areas of a city.  While these transmitters might reach 20 miles or more, for large cities the wireless signal would not carry well to the suburbs.  Therefore, repeaters might be used at key points in a city suburbs far from the central downtown antenna to amplify the signals and ensure strong signals being sent and received.