[ fon ]
/ fɒn /


a unit for measuring the apparent loudness of a sound, equal in number for a given sound to the intensity in decibels of a sound having a frequency of 1000 cycles per second when, in the judgment of a group of listeners, the two sounds are of equal loudness.

Origin of phon

First recorded in 1930–35, phon is from the Greek word phōnḗ voice

Definition for phon (2 of 3)

Definition for phon (3 of 3)


variant of phono- before a vowel: phonic. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for phon

British Dictionary definitions for phon (1 of 2)


/ (fɒn) /


a unit of loudness that measures the intensity of a sound by the number of decibels it is above a reference tone having a frequency of 1000 hertz and a root-mean-square sound pressure of 20 × 10 –6 pascal

Word Origin for phon

C20: via German from Greek phōnē sound, voice

British Dictionary definitions for phon (2 of 2)


abbreviation for

Also: phonet phonetics
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medicine definitions for phon



Variant ofphono-
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for phon


[ fŏn ]

A unit of apparent loudness. The loudness of a signal in phons is equal to the intensity in decibels of a 1,000-hertz tone judged to be as loud as the signal being measured.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.