Century

A century was a period of time equal to one hundred years.

When the Fourth Doctor got his age confused between 736 and 739, Romana I, who herself was "nearly" 140, observed that counting one's age would get a "little bit foggy" after the first few centuries. (TV: The Ribos Operation)

Demonstrating the TARDIS to Rose Tyler, the Ninth Doctor first took her a hundred years from 2005 in the 21st century to 2105 in the 22nd century. (TV: Rose)

In the late 19th century, Jack Harkness was informed by a girl that the century would turn twice before he found the Doctor. (TV: Fragments) Indeed, he ultimately reunited with the Tenth Doctor in 2008. (TV: Utopia)

On the night of 31 December 1999, Alex Hopkins, just before commiting suicide, left Torchwood Three as a "gift" to Jack for a century of service as a field operative. (TV: Fragments)

On Christmas 1851, Jackson Lake predicted that the appearance of the CyberKing would become a part of history to be spoken of for centuries to come, to which the Tenth Doctor remarked "Yeah. Funny that." (TV: The Next Doctor) Infact, his next incarnation would recall that no-one remembered the CyberKing, which he attributed to the time field. (TV: Flesh and Stone)

The Eleventh Doctor noted that he had been "rocking" his current body for centuries prior to the Siege of Trenzalore. (TV: The Time of the Doctor)

Following the Doctor's regeneration into the Twelfth Doctor, Vastra noted that he had "walked this universe for centuries untold." (TV: Deep Breath)