bastionEnglishOxford American Thesaurusbastion noun 1 he had fortified the stronghold with ditches and bastions: rampart, bulwark, parapet, fortification, buttress, outwork, projection, breastwork, redoubt, barbican, stockade, palisade; rare bartizan. 2 the last bastion of male-only suffrage in Europe: stronghold, bulwark, defender, support, supporter, guard, protection, protector, defense, prop, mainstay.