The Collaborative International Dictionary of English v.0.48:

loudspeaker \loud"speak*er\ n.
   A device which converts electrical signals into sounds loud
   enough to be heard at a distance, usually outdoors; it is
   used to amplify or transmit over a distance speech from a
   person, who is typically speaking into a microphone.
   Sometimes it is used to play recorded speech or music.

   Syn: speaker, speaker unit, loudspeaker system, speaker
        system.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

loudspeaker
    n 1: electro-acoustic transducer that converts electrical
         signals into sounds loud enough to be heard at a distance
         [syn: loudspeaker, speaker, speaker unit,
         loudspeaker system, speaker system]

Moby Thesaurus II by Grady Ward, 1.0:

30 Moby Thesaurus words for "loudspeaker":
   acoustical network, capacitor speaker, coaxial speaker, cone,
   crossover network, diaphragm, dynamic speaker, earphone,
   electrodynamic speaker, electromagnetic speaker,
   electrostatic speaker, excited-field speaker,
   full-fidelity speaker, headphone, headset, high-fidelity speaker,
   high-frequency speaker, horn, low-frequency speaker,
   midrange speaker, monorange speaker, moving-coil speaker,
   permanent magnet speaker, speaker, speaker system, speaker unit,
   triaxial speaker, tweeter, voice coil, woofer



The Free On-line Dictionary of Computing (30 December 2018):

loudspeaker

    An electromechanical device for converting
   an electrical signal into sound.

   (2008-10-09)