Frequency-hopping spread spectrum

Frequency hopping spread spectrum is a method of transmitting data wirelessly, using many different frequencies. After a given time, the transmitter and receiver change the frequency on which they transmit the signal. They do this in a seemingly random way, but both have agreed on the order in which they use the frequencies.
Technlogies such as Bluetooth use it.
It is one of the technologies generally referred to as Spread spectrum.