listener

noun

1. Someone who listens, especially to a speech or a broadcast.

   “[…] she would set herself going, telling the most interminable stories, until the last listener was fast asleep[…]”

   “And then her words tumbled out in a passion of communication, as though she hurried before her listener could be taken away.”

2. A function that runs in response to an event; an event handler.
3. (slang)A person's ear.

   “Fancy Gazette, quoted in 1823, John Badcock, Slang, a Dictionary of the Turf, the Ring, the Chase, the Pit, of Bon-Ton, and the Varieties of Life Gas now planted his favourite hit under the left listener of his antagonist, which sent him to dorse.”

4. (formal)A musical anthology.