loud·hail·er
noun/ˌlaʊdˈheɪlə(r)/
/ˌlaʊdˈheɪlər/
(British English) (North American English bullhorn)
(also megaphone British and North American English)
- a device for making your voice sound louder, that is wider at one end, like a cone, and is often used at outside events
电子喇叭；扩音器