Battery: a device that produces electricity to provide power for radios, cars, etc.
Noun: a rechargeable battery
Compass: a device for finding direction with a needle that can move easily and that always points to magnetic north
Noun: Today I saw a compass
Candle: a stick-shaped piece of wax with a wick (= piece of string) in the middle of it that produces light as it slowly burns
Noun: Shall I light a candle?