A megaphone in the strict sense is a simple cone that channels the voice with no electronics. A bullhorn is battery-powered, with a microphone and amplifier. In practice megaphone is used for both, and bullhorn — chiefly American — is the more specific word for the powered version.
The core difference
A shape and a powered device, with one word doing double duty.
- megaphone — strictly the unpowered cone; commonly used for both types.
- bullhorn — the powered kind, with microphone, amplifier and battery. Mainly American usage.
How the unpowered one works
A plain cone amplifies nothing. It improves how efficiently the voice couples to the air and directs the sound forward instead of letting it spread, which makes it louder in front and quieter behind. Cheerleaders' cones and old ships' speaking trumpets work on that principle alone.
Figurative use
Megaphone is the one that carries figuratively — "megaphone diplomacy", "a megaphone for their views". Bullhorn rarely does, which is a clue to which word feels more general.
Frequently asked questions
Is a bullhorn the same as a megaphone?
A bullhorn is a powered megaphone. Strictly, a megaphone is the unpowered cone, though the word is used for both.
Does an unpowered megaphone actually make you louder?
It directs the sound forward rather than amplifying it, which makes you louder in front and quieter behind.
Which word is used figuratively?
Megaphone — as in megaphone diplomacy. Bullhorn rarely appears figuratively.