An ear was a sensory organ associated with hearing. There was fluid inside that affected a persons' balance. (PROSE: A Bright White Crack)
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)
The top of the Seventh Doctor's ear was singed when the War Chief fired his laser cane at him and he ducked. The Doctor healed it with some Sisterhood Salve. (PROSE: Timewyrm: Exodus)
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)
Abzorbalovians such as the Abzorbaloff appeared to have pointed ears. (TV: Love & Monsters)
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) The Tenth Doctor claimed that his predecessor was literally "all ears". (AUDIO: Death in the New Forest)
Vulcans such as Spock were externally distinguished from humans by their pointed ears. (COMIC: Assimilation²)
The ears of a Fostarone turned blue when they lied. (PROSE: Ghosts of India)
IMC shock trooper Sharon Kreig collected ears, one from each action she participated in; she had thirty-eight in total. (PROSE: Lucifer Rising)
Upon discovering that the Eleventh Doctor was bald, having shaved his head out of boredom, Clara Oswald demanded that he put his wig back on, unnerved by his now prominent ears which she compared, much to his delight, to rocket fins. (TV: The Time of the Doctor)
According to a joke book which the Doctor and Yaz became trapped within, a Dalek once said "TAKE YOUR FINGER OUT OF YOUR EAR WHEN I AM EXTERMINATING YOU!" to a petrol pump. (PROSE: Knock! Knock! Who's There?)
The Eleventh Doctor once told the recipients of a letter to keep half an eye peeled and half an ear open in case he checked up on them. (PROSE: Hello!)