Third Time Lord
The titles of First Time Lord, Second Time Lord and Third Time Lord referred to "the three most superior Time Lords".
A First, Second and Third Time Lord formed the High Tribunal (PROSE: Doctor Who and the Doomsday Weapon) who sentenced the Second Doctor to his exile on Earth. The Third Time Lord present during these events, (TV: The War Games) Chancellor Socra, (PROSE: The Legacy of Gallifrey) still held the title, but now in a new incarnation, when he and the other two pondered what to do about the Doomsday Weapon crisis. (TV: Colony in Space, PROSE: Doctor Who and the Doomsday Weapon) However, during the First Omega Crisis, Socra, (PROSE: The Legacy of Gallifrey) referred to as Chancellor, once again looked just as he had (TV: The Three Doctors) during the Doctor's trial. (TV: The War Games)