bastion Synonyms

citadel base complex presidio parapet palisade outwork mainstay keep guard fortress fortification fort prop protection fortifications tower of strength wall vallation tower support stronghold rock resistance redoubt rampart fastness earthwork barricade barbican barbette barbacan banquette balustrade balistraria alcazar aegis acropolis barrier bartizan base donjon dike defense defence castle bunker bulwark breastwork blockhouse battlement