Definition of side tone in English:

side tone

noun

  • [mass noun] Feedback in a telephone receiver, in particular the reproduction of the user's own voice.

    ‘a little side tone is useful’
    • ‘This subtractive procedure can eliminate most side tone to the point where, in a well set-up system, the listeners voice is removed completely.’
    • ‘The side tone is that made from vibrations moving sideways through the bar rather that along it, and is usually too weak to be heard on its own.’