loudspeaker

Short definition from Wiktionary

Noun

1. 1
   An electromechanical transducer that converts an electrical signal into audible sound.
2. 2
   Any such transducer that is loud, as opposed to quiet ones such as those found in headphones.
3. 3
   An encasing containing one or more loudspeaker devices and usually other electrical equipment such as a driver.