2 (number)

2 was a number.

7 was not divisible by 2. (PROSE: And Then Again)

The Ux were a duo-species, meaning there were always only two of them. (TV: The Battle of Ranskoor Av Kolos)

The Boneless came from a universe with only two dimensions. (TV: Flatline)

The Twelfth Doctor once told Bill that "eleven plus two" was an anagram of "twelve plus one", to which Bill responded that both of these were equal to 13. (COMIC: Harvest of the Daleks)

Humanoids had two arms, and were bipedal, meaning they had two legs, and binocular, meaning they had two eyes. (TV: Kinda) They also had two ears. (TV: Rose) The resulting symmetry played a large part in attractiveness. (TV: World Enough and Time)

Time Lords had a binary vascular system, meaning they also had two hearts. (TV: Spearhead from Space, et al.) On discovering the Tenth Doctor had two hearts, Jackie Tyler wondered if there was anything else he had two of. (TV: The Christmas Invasion)

The Horrorkons had two heads per body, (COMIC: Monsters of Gurnian) as did the Terrorkons (COMIC: Impasse) and the Aplans. (TV: The Time of Angels)

Planets with two moons included Colony 34, (AUDIO: LIVE 34) Crimson Heart, (TV: Death of the Doctor) Funderell, (AUDIO: The Skin of the Sleek) Gallifrey, (PROSE: Cat's Cradle: Time's Crucible) Juno 10, (AUDIO: Penny Wise, Pound Foolish) Liberius, (PROSE: First Born) Mendorax Dellora, (TV: The Husbands of River Song) Skaro, (AUDIO: Davros, Purity) Symbios (AUDIO: The Crimes of Thomas Brewster) and Trenzalore. (PROSE: Strangers in the Outland)

The countdown towards the Ninth Doctor's eviction on Big Brother counted from 6 to 0, going through 5, 4, 3, 2, and 1. (TV: Bad Wolf)

After the defeat of the Slitheen family on 7 March 2006, Mickey Smith (TV: ) wrote on his website the morning after, confessing that he had "been in two minds" recently, finding himself doubting the evidence, facts, and secrets he uncovered, although he was reassured by the emails he received, even though he sometimes deleted them, knowing vaguely what was in them. (PROSE: )

In 2007, Elton Pope recalled his experience of the 5 March 2005 incident, which he noted was "two years ago". (TV: )

"ChatGuest1" repaired his broken radio (GAME: ) in Pete's World (TV:, PROSE: ) in 2007 (TV: , etc.) by pressing the FM button twice. This solution was found by the readers of Defending the Earth! from the Doctor's universe, after going onto www.internationalelectromatics.co.uk and troubleshooting the problem with the IE ATSS. (GAME: )

During the COVID-19 pandemic in 2020, humans had to stand at least two metres away from each other to prevent passing on the virus. (PROSE: )

In an emergency transmission sent by the TARDIS, the Thirteenth Doctor listed 5 things that she did in any worrying situation. The second was telling jokes, especially bad ones, which she claimed to be 'brilliant' at. (WC: )

Behind the scenes
Though unremarked in the short story Daisy Chain, two is also the third number in the Fibonacci sequence. Also, unremarked in the audio drama The Haunting is that two is a prime number.