noun: (automotive) A motor with hemispherical combustion chambers. A piston engine internal combustion engine with hemispherical piston cylinder heads.
noun: (automotive) A combustion chamber with the hemispherical cylinder head from such an engine.
noun: (automotive) A hemispherical cylinder head from such a motor.
noun: (automotive) A vehicle equipped with such a motor engine.
noun: (by extension) Domed versions of the above that have cylinder heads that are not exactly hemispherical
