Noise that distresses is an ASSAULT The meaning of the word “Noise” Word History:  Those who find that too much noise makes them ill will not be surprised that the word noise can possibly be traced back to the Latin word nausea, "seasickness, feeling of sickness." Our words nausea and noise are doublets, that is, words borrowed in different forms from the same word. Nausea, first recorded probably before 1425, was borrowed directly from Latin. Noise, first recorded around the beginning of the 13th century, came to us through Old French, which explains its change in form. Ambient noise level is measured with a sound level meter. It is usually measured in dB above a reference pressure level of 0.00002 Pa, i.e., 20 μPa (micropascals) in SI units. A pascal is one newton per square metre. Ambient noise levels are usually measured using a frequency weighting filter, the most common being the A- weighting scale, such that resulting measurements are denoted dBA, or decibels on the A-weighting scale.  Ambient Noise   In atmospheric sound transmission or noise pollution, ambient noise level is the sound pressure level at a given location, normally specified as a reference level to study a new intrusive sound source.