modulation

/M AA0 JH AH0 L EY1 SH AH0 N/
noun
  1. 1

    The process of applying a signal to a carrier, modulating.

  2. 2

    The variation and regulation of a population, physiological response, etc.

  3. 3

    A change in key.

Source: https://en.wiktionary.org/wiki/modulation