The term 'microscope piece' can be summarized by the four-letter word 'LENS'. A LENS is an optical device that focuses or disperses a light beam through refraction. It is typically made from a piece of transparent material, such as glass or plastic, and is used in a variety of instruments, including microscopes, cameras, and eyeglasses. In microscopes, lenses are used to magnify objects, allowing them to be seen more clearly.