mainland
- n the main land mass of a country or continent; as distinguished from an island or peninsula
mainland china
- n a communist nation that covers a vast territory in eastern Asia; the most populous country in the world
mainmast
- n the chief mast of a sailing vessel with two or more masts
mainsheet
- n (nautical) a line (rope or chain) that regulates the angle at which a sail is set in relation to the wind