Glossary of Terms:
 
balanced
1) Having a pleasing amount of low frequencies compared to mid-range frequencies and high frequencies.
2) Having a pleasing mixture of the various instrument levels in an audio recording.
3) Having a fairly equal level in each of the stereo channels.
4) A type of connection between electronic devices, using shielded, twisted-pair cable, to reduce interference. With this connection, one wire (+) is driven equally to the other wire (-), but is 180 degrees out of phase with the other wire. Since any interference picked up will be in the same phase on both wires, the differential amplifier at the balanced input cancels out the noise, but amplifies the audio signal. The ground is used only for shielding and safety.
Source: Recording Institute of Detroit

Also refered as:
  low impedance
Related terms:
  1/4-inch jack   XLR connector   balancing   high impedance   input   output   unbalanced