The shutter is in the camera and opens and closes to let light in or keep light out. Shutter speed refers to how long the shutter is open and letting light in. An example of a very fast shutter speed would be 1/4000 (seconds), and a slow shutter speed would be 10" (seconds).
1/4000 3" the fast shutter allows for the photographer to capture The long shutter speed allows for the photographer to action and get a clear and high quality photo. captures light in a sort of "painting". usually requires a tripod to get a clear, crisp photo (but not always).