An ear was a sensory organ associated with hearing.
The Fourth Doctor thought his nose was an improvement over that of his prior incarnation, but was unsure whether his ears were as well. (TV: Robot)
While visiting the Quadrant in 1987, Chris Cwej got an earring in his right ear. At the time in England, this was an indication that the wearer was gay, but he was initially unaware of the significance. (PROSE: Damaged Goods)
All Remote wore receivers in their earlobes. (PROSE: Interference - Book One, The Book of the War)
To gain the Tenth Doctor's trust whilst they were in the Library in the 51st century, River Song whispered his true name into his ear. (TV: Forest of the Dead)
When the War Doctor regenerated he hoped his ears would be less conspicuous. (TV: The Day of the Doctor) The Ninth Doctor referred to the size of his ears when he met Rose Tyler. (TV: Rose) Mickey Smith once referred to him as "big ears". (TV: Boom Town)
Vulcans such as Spock were externally distinguished from humans by their pointed ears. (COMIC: Assimilation²)