A lamp is a small appliance that holds an electric bulb and produces light. Your desk lamp might provide enough light for you to read by at night, or you may have to turn on a floor lamp too after the sun goes down.
Today, most lamps use electricity and a light bulb to shine the light that we all need to work and live comfortably after daylight fades. There are also older-style oil lamps and gas lamps, which are more typically described as lanterns. The Greek root of lamp is lampas, "torch or beacon" and also "meteor," from lampein, "to shine."