Bandpass
A filter that transmits a particular frequency band and attenuates frequencies that lie on both sides of that band.

Bridgeable to Mono
Function allowing two outputs on a stereo amplifier to be combined to produce a more powerful mono signal

Crossover
A filter which is able to separate out high and low frequencies to allow them to be sent to different amps or speakers

Gain
Signal amplification, expressed in decibels (dB)

MOSFET
Amplifier power supply designed for improved performance

OHM
The measurement of electrical resistance

PMPO
Peak Power or Maximum Power Output that can be sustained for a short time from an amplifier. Not generally regarded as the industry standard.

Pre-Amp Output (pre-out)
An output on the head unit enabling an amplifier to be added

RMS
Root Mean Square - the benchmark for measuring an amplifier's output over a sustained period of time

Signal To Noise Ratio
Ratio of background hiss to the full output power