A microphone, used to amplify a person’s voice when speaking or singing, such as when making a speech, performing a concert, or delivering a stand-up comedy routine.

Previously shown with music notes on most platforms, implying it to be used for a singer / singing. Today only Twitter's design retains these notes.

WhatsApp uses this emoji in push notifications to indicate that you have received a voice message.

Microphone was approved as part of Unicode 6.0 in 2010 and added to Emoji 1.0 in 2015.