(A piece of) waste or unowned land; an uninhabited or desolate area.

St Thomas (a,also of) Watering(s) and variants: the site of public executions for Surrey until the 18th cent. Hence in allusive use: death by…

Steps on the Aventine Hill leading to the Tiber, to which the bodies of executed criminals were dragged to be thrown into the river.

the dock (at Wapping) where criminal sailors were executed.

A pit, gulf. Hence. A deep pit at Athens, into which criminals condemned to death were thrown.