earmuff

noun

1. 1.A garment to keep the ears warm.
2. 2.A garment or part worn over a single ear.
3. 3.A sound-deadening cup or a pair of such cups worn over the ear or ears.
4. 4.Objects designed to cover a person's ears for protection against cold or noise. They consist of a thermoplastic or metal head-band, that fits over the top of the head, and a pad at each end, to cover the external ears.