megaphone
megaphone is an audio electronics or horn loudspeaker.
Also recorded as mega phone; bullhorn; loudhailer; loud hailer.
Overview
Electroacoustic handheld device for amplifying the voice.
In detail
Recorded constituent parts are microphone and loudspeaker.
Sources
Each source is named with the standing the house places on it, so the evidence can be weighed rather than taken on trust.
reference work · Reputable secondary · Wikipedia
“Megaphone”, English Wikipedia, consulted as further reading
Consult the sourcereference work · Reputable secondary · Wikidata
Wikidata, structured authority record Q216217: megaphone
Consult the source