Window of the Sunset
The Window of Sunset was a waterfall which concealed the Gondorian outpost of Henneth Annûn from Sauron. The waterfall keeps the Ithilien Ranger's base completely hidden and feeds the pool which it overlooks. This was where Sam and Frodo were taken when they were captured by the Rangers of Ithilien.
In Sindarin Window of the West translates as Henneth Annûn, which is the name of the outpost.