Still point in time
From Tardis Wiki, the free Doctor Who reference
According to Dorium Maldovar, still points in time made it easier to create fixed points in time. The Kovarian Chapter of the Silence used one such point in space-time — 5:02 PM on 22 April 2011 by Lake Silencio — to make the Eleventh Doctor's death there a fixed point. (TV: The Wedding of River Song)
