(just say the letters to pronounce)
An abbreviation for Noise Reduction Coefficient, which is a way of measuring the amount of sound energy absorbed or reflected by a particular material or element, or — more specifically — the surface of that element. The higher the NRC number, the better the acoustic performance. Something with an NRC of 1 indicates perfect absorption, while a material with an NRC of 0 indicates total reflection. For example, terazzo — a hard surface — would have a lower NRC rating than shag carpet.