Senior Time Lord

From Tardis Wiki, the free Doctor Who reference
The Chancellor and the President. (TV: The Three Doctors)

The President and Chancellor were recognised as Senior Time Lords, whom commanded younger Junior Time Lords. (PROSE: The Three Doctors)

By another account, the titles of First Time Lord, Second Time Lord and Third Time Lord referred to "the three most superior Time Lords". (PROSE: Doctor Who and the Doomsday Weapon)