earpiece

noun3

1. •
   A speaker placed inside or held near to the ear.

   • Holding the earpiece to my ear, I could hear him speaking clearly.
2. •
   A receiver of a telephone to hold near to one's ear.
3. •
   The arm on a pair of glasses that hooks over the ear to hold them in place.

   • My glasses won't stay on, as I've broken the left earpiece.