a subjective unit of loudness equal to that experienced by a normal person hearing a 1 kHz tone at 40 dB
Word origin
C20: from Latin sonus a sound
sone in American English
(soʊn)
US
noun
a unit of loudness, subjectively determined, equal to the loudness of a sound of one kilohertz at 40 decibels above the threshold of hearing of a given listener