1) Aural warmer 2) Canal protector 3) Covering 4) Drum cover 5) Half a pair of warmers 6) Half a winter warmer 7) One of a warming pair 8) Part of a winter warmer 9) Winter warmer 10) Winter wear 
[n] - either of a pair of ear coverings (usually connected by a headband) that are worn to keep the ears warm in cold weather
Photograph courtesy of Draper.co.ukHearing protector worn over the pinna of an ear. See also: Ear, Earplug, Hearing, Hearing Protector.
noun either of a pair of ear coverings (usually connected by a headband) that are worn to keep the ears warm in cold weather