Decibel

A decibel is a way of measuring loudness. For example, a car honk is about as loud as 80 decibels. That means it is 80 times louder than the quietest sound a person can hear. The loudest sound a person can stand is about 120 decibels. That's really loud, like a jet plane taking off.

Related topics others have asked about:

Apparent magnitude, Cent (music), DB drag racing, Day-night average sound level, Day–evening–night noise level, Decade (log scale), Loudness, Neper, One-third octave, PH, Phon, Richter magnitude scale