Maximum power rating: A value which means almost nothing, but is used nonetheless by manufacturers to entice the unsuspecting into purchasing their product based solely on the big number. Technically, it is the maximum wattage that an audio component can deliver/handle as a brief burst during a musical peak. Most reputable manufacturers will provide both an RMS and Max power rating. Typically, the given value for the maximum power rating is twice to three times that of RMS.
Microfarads: a measurement of capacitance (XC*10^-6).
Midrange (mids): the frequency range above bass but below treble that carries most of the identifying tones of music or speech. It is usually from 200Hz to 4kHz.
Millihenries (mH): a measurement of inductance (XL*10^-3).
Mms: the moving mass of a driver assembly.
Mono: monophonic sound. A method for reproducing sound where the signals from all directions or sources are blended into a single channel.
MOFSET: Metal Oxide Semiconductor Field Effect Transistors. Used in most modern, quality car audio amplifiers in the power supply. MOSFET's run cooler than normal bipolar transistors, and have a faster switching speeds and higher slew rates.
Octave: a range of tones where the highest tone occurs at twice the frequency of the lowest tone.
Ohm: a unit of electrical resistance or impedance.
Ohm's Law: a basic law of electric circuits. It states that: the current [I] in amperes in a circuit is equal to the voltage [V] in volts divided by the resistance [R] in ohms; thus, I = V/R.
Oversampling: It’s used in DAC systems. Increases signal frequency, making it easier for conversion circuitry and ancillary systems to filter out unwanted signals.
Out of Phase: When your speakers are mounted in reverse polarity, i.e., one speaker is wired +/+ and -/- from the amp and the other is wired +/- and -/+. Bass response will be very thin due to cancellation.
Output: the sound level produced by a loudspeaker.