Definitions
1.NounA motor with hemispherical combustion chambers. A piston engine internal combustion engine with hemispherical piston cylinder heads.
2.NounA combustion chamber with the hemispherical cylinder head from such an engine.
3.NounA hemispherical cylinder head from such a motor.
4.NounA vehicle equipped with such a motor engine.
5.NounDomed versions of the above that have cylinder heads that are not exactly hemispherical