A strongly fortified defensive structure.

synonym: fastness.

Roget 752: prison, prison house; jail, gaol, cage, coop, den, cell; stronghold, fortress, keep, donjon, dungeon, Bastille, oubliette, bridewell^†, house of correction, hulks, tollbooth, panopticon^†, penitentiary, guardroom, lockup, hold; round house, watch house, station house, sponging house; station; house of detention, black hole, pen, fold, pound; inclosure etc. 232; isolation (exclusion) 893; penal settlement, penal colony; bilboes, stocks, limbo, quod [Lat.]; calaboose, chauki^†, choky^†, thana^†; workhouse [U.S.].    Newgate, Fleet, Marshalsea; King's Bench, Queen's Bench.    bond; bandage; irons, pinion, gyve, fetter, shackle, trammel, manacle, handcuff, straight jacket, strait jacket, strait-jacket, strait-waistcoat, hopples^†; vice, vise.    yoke, collar, halter, harness; muzzle, gag, bit, brake, curb, snaffle, bridle; rein, reins; bearing rein; martingale; leading string; tether, picket, band, guy, chain; cord etc. (fastening) 45; cavesson^†, hackamore [U.S.], headstall, jaquima [U.S.], lines, ribbons.    bolt, deadbolt, bar, lock, police lock, combination lock, padlock, rail, wall, stone wall; paling, palisade; fence, picket fence, barbed wire fence, Cyclone fence, stockade fence, chain-link fence; barrier, barricade.    drag etc. (hindrance) 706.    ... show more

Roget 717: defense, protection, guard, ward; shielding etc. v.; propugnation^†, preservation etc. 670; guardianship.    area defense; site defense.    self-defense, self-preservation; resistance etc. 719.    safeguard etc. (safety) 664; balistraria^†; bunker, screen etc. (shelter) 666; camouflage etc. (concealment) 530; fortification; munition, muniment^†; trench, foxhole; bulwark, fosse^†, moat, ditch, entrenchment, intrenchment^†; kila^†; dike, dyke; parapet, sunk fence, embankment, mound, mole, bank, sandbag, revetment; earth work, field-work; fence, wall dead wall, contravallation^†; paling etc. (inclosure) 232; palisade, haha, stockade, stoccado^†, laager^†, sangar^†; barrier, barricade; boom; portcullis, chevaux de frise [Fr.]; abatis, abattis^†, abbatis^†; vallum^†, circumvallation^†, battlement, rampart, scarp; escarp^†, counter-scarp; glacis, casemate^†; vallation^†, vanfos^†.    buttress, abutment; shore etc. (support) 215.    breastwork, banquette, curtain, mantlet^†, bastion, redan^†, ravelin^†; vauntmure^†; advance work, horn work, outwork; barbacan^†, barbican; redoubt; fort-elage [Fr.], fort-alice; lines.    loophole, machicolation^†; sally port.    hold, stronghold, fastness; asylum etc. (refuge) 666; keep, donjon, dungeon, fortress, citadel, capitol, castle; tower of strength, tower of strength; fort, barracoon^†, pah^†, sconce, martello tower^†, peelhouse^†, blockhouse, rath^†; wooden walls.    [body armor] bulletproof vest, armored vest, buffer, corner stone, fender, apron, mask, gauntlet, thimble, carapace, armor, shield, buckler, aegis, breastplate, backplate^†, cowcatcher, face guard, scutum^†, cuirass, habergeon^†, mail, coat of mail, brigandine^†, hauberk, lorication^†, helmet, helm, bassinet, salade^†, heaume^†, morion^†, murrion^†, armet^†, cabaset^†, vizor^†, casquetel^†, siege cap, headpiece, casque, pickelhaube, vambrace^†, shako etc. (dress) 225.    bearskin; panoply; truncheon etc. (weapon) 727.    garrison, picket, piquet; defender, protector; guardian etc. (safety) 664; bodyguard, champion; knight-errant, Paladin; propugner^†.    bulletproof window.    hardened site.    ... show more

Dutch: bolwerk, fort
Polish: twierdza, forteca