The principal mast in a ship or other vessel.

The middle mast of a ship; the after-mast of a brig or schooner.

The principal mast of a sailing ship.

Second mast from the bow of a ship, barque or schooner.

the chief mast of a sailing vessel with two or more masts

usually, the principal and the heaviest mast of two or more. In yawls and ketches, the forward mast is the mainmast; in schooners and vessels with more than two masts, it is the second mast from forward.

(or Main) - The tallest mast on a ship.

Spars , Parts Mainsail Sails , Rigging

Second mast aft from the bow.

the largest, and main, mast.

Aboard the three-masted Concordia, the middle of the three

The tallest mast on the ship. cf foremast and mizzenmast. (See rigging illustration.)

the tallest mast of the ship; on a schooner, the mast furthest aft.