Definition of phon in English:

phon

noun

  • A unit of the perceived loudness of sounds.

    ‘Coincidentally, one phon is approximately the smallest detectable difference in loudness.’
    ‘The use of the phon as a unit of loudness is an improvement over just quoting the level in decibels.’

Origin

1930s from Greek phōnē ‘sound’.

Pronunciation

phon

/fɒn/