(communications) The ratio of the power at one point in a transmission system to the power at a point farther along the line; usually expressed in decibels. The actual power that is lost in transmitting a signal from one point to another through a medium or along a line. Also known as loss.
Of a partition, the number of decibels by which sound (incident on the partition) is reduced in transmission through it; a measure of the sound insulation value of the partition—the higher the number, the greater the insulation value.