Speaker

Noun

1. One who speaks.

   "There were three different speakers, but I couldn't make out their accents."

2. Loudspeaker.

   "She lost her hearing after standing too close to the speaker at the festival."

3. Speakerphone.

   "you're on speaker"

4. The chair or presiding officer of certain legislative bodies, such as the U.K. House of Commons or the U.S. House of Representatives.
5. One who makes a speech to an audience.

   "hired speaker; motivational speaker"