C54 or C-54 may refer to: , an Admirable-class minesweeper of the Mexican Navy Caldwell 54, an open cluster in the constellation Monoceros Douglas C-54 Skymaster, an American transport aircraft Giuoco Piano, a chess opening JNR Class C54, a Japanese steam locomotive Holidays with Pay (Sea) Convention, 1936 of the International Labour Organization Uterine cancer