kuò​yīn​qì

loudspeaker

扩音器 (擴音器) kuò​yīn​qì
loudspeaker noun
a device such as a megaphone or speaker used to project sound and make it audible at a distance

The teacher used a megaphone to maintain order on the playground.

microphone noun
a transducer that converts sound waves into electrical signals

The teacher stood in the middle of the playground with a megaphone, directing the students to assemble.

Frequency

Movie subtitles
1.64 per million appears in 1% of films
Written text
0.735 per million

Sources

Definitions
CC-CEDICT