Frame rate is a way of describing video. It refers to the number of images, called frames, that are being shown every second. It is measured in frames per second, or FPS.
Early silent movies were shown at a frame rate between 16 and 24 frames per second. This went up to 20 and 26 FPS later. When movies with sound came out 24 FPS became the standard because it was in the middle of the frame rates theaters used.
Video games are usually played at a frame rate of 60 frames per second. This is because it is a very common refresh rate (display speed) for computer monitors. They also can run at 30 FPS, or even more, such as 144 FPS or 240 FPS, depending on what the monitor can handle. If the frame rate is higher than the refresh rate, not all of the frames can be shown. If two or more frames are displayed at the same time, it can cause problems like screen tearing.