also: メガフォン
noun
megaphone; bullhorn; loudhailer
A handheld cone-shaped device for amplifying the voice, used in sports events, demonstrations, or by tour guides.
先生はメガホンを使って生徒たちに指示を出した。
The teacher used a megaphone to give instructions to the students.
デモ隊がメガホンでシュプレヒコールを繰
The demonstrators chanted slogans through megaphones.