The shutter speed is the amount of time per frame (technically, per field when dealing with interlaced video) that the CCD spends capturing the image. The longer the shutter is open, the more light is sampled and therefor the image has less noise, but a slow shutter speed also makes the image more blurry if there is a lot of motion. When choosing a shutter speed, it is good to find a balance between less noise and less blurriness.
Unlike cameras, camcorders do not have physical shutters. Shutter speed is measured in fractions of a second that the shutter is open. A camcorder might give you a range of shutter speeds from 1/60th of a second to 1/10,000th of a second, or even faster or slower.