What term describes the undesired creation of new frequency components when one or more signals enter a non-linear device?

Intermodulation (often called 'intermod') occurs when two or more signals mix inside a non-linear device, such as an overdriven amplifier, a corroded connection, or an overloaded receiver front end. This unintended mixing generates completely new signals at frequencies that are sums and differences of the original signals and their harmonics. These newly created frequency components can cause severe interference on channels far away from the original transmissions. For example, two strong nearby signals might mix to produce a third phantom signal right on the frequency you are trying to listen to. Aliasing is a digital sampling artifact, and phase or linear distortion affects the integrity of a single signal's waveform rather than creating entirely new frequency components through mixing.