In baseball, a fence, prop. at least 90 feet behind the home base, to stop the balls that pass the catcher; also, the catcher himself. [Webster 1913 Suppl.]
In rounders, the player who stands immediately behind the striking base. [Webster 1913 Suppl.]
In cricket, the longstop; also, the wicket keeper. [Webster 1913 Suppl.]

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THESAURUS

backstop

advocate, aegis, arch dam, arm guard, back, bamboo curtain, bank, bar, barrage, barrier, bear-trap dam, beaver dam, boom, breakwater, breastwork, brick wall, buffer, bulkhead, bulwark, bumper, champion, cofferdam, contraceptive, copyright, crash helmet, cushion, dam, dashboard, defense, dike, ditch, dodger, earthwork, embankment, face mask, fence, fender, finger guard, foot guard, fuse, gate, goggles, governor, gravity dam, groin, guard, guardrail, hand guard, handrail, hard hat, helmet, hydraulic-fill dam, insulation, interlock, iron curtain, jam, jetty, knee guard, knuckle guard, laminated glass, leaping weir, levee, life preserver, lifeline, lightning conductor, lightning rod, logjam, mask, milldam, moat, mole, mound, mudguard, nose guard, pad, padding, palladium, parapet, patent, pilot, portcullis, preventive, prophylactic, protective clothing, protective umbrella, rampart, roadblock, rock-fill dam, safeguard, safety, safety glass, safety plug, safety rail, safety shoes, safety switch, safety valve, screen, seat belt, seawall, shield, shin guard, shutter dam, side with, stone wall, sun helmet, umbrella, uphold, wall, weir, wicket dam, windscreen, windshield, work

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