What is a camera's "shutter"?

What is a camera's "shutter"?

Mark Comon (Vice President, Paul's Photo, Torrance, CA) gives expert video advice on: Why would I use the "image stabilizer" feature?; How do various image stabilizers differ?; What shutter speed range do I need for my digital camera? and more...

With digital cameras, the shutter of a camera controls the amount of time that light comes through the lens. The longer the shutter is open for, the more the light that comes through. The shorter or less amount of time the shutter is open, the less light comes through. The shutter also controls the action stopping ability. The faster or smaller the shutter speed, the more action you stop. The longer the shutter speed or the more light that comes in, the less action you can stop.