Frame rate (also known as frame frequency) is the frequency (rate) at which an imaging device produces unique consecutive images called frames. Human eye can't see picture changes after the framerate is more than ~24fps. The term applies equally well to computer graphics, video cameras, film cameras, and motion capture systems. Frame rate is most often expressed in frames per second (FPS), and is also expressed in progressive scan monitors as hertz (Hz).
In American TV system NTSC the framerate is appx. 29.97fps and in European PAL system the framerate is 25fps.