Canonicity

Canonicity was a concept of interest to the Time Lords. There existed a Tower of Canonicity in the Capitol, twin to the Tower of Likelihood. (PROSE: The Blue Angel) The Sixth Doctor once expressed doubt on whether something to do with Hecate (about which he didn't elaborate) was “canonical”. (AUDIO: Doctor Who and the Pirates)

According to one account, the concept of canonicity could also be applied to works of fiction; this same account, holding that Iris Wildthyme's life was in truth a multi-platform fiction franchise, noted that even a super-fan “hardly knew what was canonical”. (PROSE: From Wildthyme with Love)