The Free On-line Dictionary of Computing (30 December 2018):

frame rate

    The number of frames of an animation which are
   displayed every second, measured in frames per second (fps).
   The higher the frame rate, the smoother the animation will
   appear but the more processing power and system bandwidth is
   required.

   At less than 30 fps, the human eye can see the new pictures
   coming onto the screen.

   (2000-02-02)