Definition:
A "royal mast" is a term used in sailing and refers to a specific part of a ship's mast. It is the topmost mast above the topgallant mast. Essentially, it is a tall structure that helps hold up the sails on the very top of the ship.
In advanced sailing terminology, knowing about the royal mast can help in understanding how ships are rigged and how they operate. Sailors often need to know the different types of masts (like main mast, foremast, and mizzen mast) and their functions.
In summary, the "royal mast" is a specific part of a sailing ship's mast.