Shutter Speed: The amount of time that she shutter is open. The longer it's open the more light is let in. Also to freeze movement in an image choose a faster shutter speed. To let the movement blur choose a slower shutter speed.
Understanding Shutter Speed
Photography - Tips
Common mistakes at every shutter speed (and the best settings you should use)
photo tips - shutter speeds
WHAT SLOW SHUTTER SPEED LOOKS LIKE: Using a slow shutter speed inside a moving car.
SLR camera shutter speed
Difference between fast and slow shutter speeds.
Demystifying Shutter Speed
Slow shutter speeds: how to achieve consistent exposures every time
The B&H Guide to Exposure: Understanding Shutter Speed | explora