noun

A projecting part of a fortification built at an angle to the line of a wall, so as to allow defensive fire in several directions.

A large area was enclosed by a defensive wall with bastions and monumental gates, and the natural sheltered harbour was extended and deepened.

rampart,bulwark,parapet,fortification,buttress,outwork,projection,breastwork,redoubt,barbican,stockade,palisade