S53 may refer to: S53 (New York City bus), serving Staten Island Dhurga language, an Australian Aboriginal language S53: Avoid exposure - obtain special instructions before use, a safety phrase Shorland S53, a British armoured car Sikorsky S-53, an American helicopter Tsonga language, a Bantu language Saviem S53, a Saviem bus model Toyota S53, a Toyota S transmission ZIS-S-53, an Anti air and Anti-tank gun