IPod

An iPod was a music storage and listening device from 21st century Earth.

Owen Harper listened to "Atlas" by Battles on his iPod while cleaning his flat. (TV: A Day in the Death)

After the death of Danny Pink, Clara Oswald observed that people "just kept walking with their iPods and their shopping bags." (TV: Dark Water)

In 5,000,000,000, Cassandra presented to fellow guests on Platform One what she identified as an iPod. With it she played Soft Cell's "Tainted Love", a traditional song, and Britney Spears' "Toxic", a ballad from Earth's classical era. (TV: The End of the World)

Other similarly named devices from that era included the iPad and the iPhone. (TV: Dark Water, Kill the Moon)

Behind the scenes
Though not made clear, iPods are an example of MP3 players.

IPod