Real-Time Strategy is explicitly not turn-based; things progress continuously without pausing. Warcraft 1-3, StarCraft 1 and 2, and the Command & Conquer series are all examples of RTS games. The other major strategy genre is TBS (Turn-Based Strategy) e.g. your Crusader Kings or your Civilization.

As the Fallout games (exclusive of Brotherhood of Steel) aren't strategy games, but RPG's, I'm not sure if there's a widely used initialism for the way combat works in the first two Fallout games— maybe TBC (Turn-Based Combat), although to me that evokes The Burning Crusade. Bethesda's Fallout games, arguably, have a variant of RTwP (Real-Time with Pause) combat, via the V.A.T.S. system.