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bullhorn vs. megaphone

[bool-hawrn] / ˈbʊlˌhɔrn /
Or bull horn

noun

  1. a directional, high-powered, electrical loudspeaker or megaphone.

[meg-uh-fohn] / ˈmɛg əˌfoʊn /

noun

  1. a cone-shaped device for magnifying or directing the voice, chiefly used in addressing a large audience out of doors or in calling to someone at a distance.

verb (used with or without object)

megaphoned, megaphoning
  1. to transmit or speak through or as if through a megaphone.