billows

/B IH1 L OW0 Z/
noun
  1. 1

    A large wave, swell, surge, or undulating mass of something, such as water, smoke, fabric or sound

verb
  1. 1

    To surge or roll in billows.

  2. 2

    To swell out or bulge.

Source: https://en.wiktionary.org/wiki/billow, https://en.wiktionary.org/wiki/billows