simultaneousness

/ˌsaɪməlˈteɪniəsnəs/
noun
  1. The quality or state of happening or existing at the same time.
    • The simultaneousness of their laughter showed they shared the same joke.
    • The simultaneousness of the two events made it impossible to attend both.
    • Scientists studied the simultaneousness of the seismic waves to understand the earthquake.
Antonyms