C33 or C-33 may refer to: Vehicles Aircraft Beechcraft C33 Debonair, an American civil utility aircraft Boeing C-33, a proposed American military transport Caspar C 33, a German trainer Caudron C.33, a French passenger biplane Douglas C-33, an American military transport Automobiles Nissan Laurel C33, a Japanese sedan Sauber C33, a Swiss Formula One car Ships , a C-class submarine of the Royal Navy Other uses Autopista C-33, a highway in Catalonia, Spain C33 road (Namibia) Caldwell 33, a supernova remnant Head and neck cancer King's Gambit Accepted, a chess opening C.3.3., the pseudonym used by Oscar Wilde to publish his poem "The Ballad of Reading Gaol"