MAIN-HOLD. That part of a ship's hold which lies near the main-hatch.

MAIN-ICE. A body of impenetrable ice apparently detached from the land, but immovable; between which and the land are lanes of water.

MAIN-JEERS. Jeers for swaying up the main-yard.

MAIN-KEEL. The principal keel, as distinguished from the false-keel and the keelson.

MAIN-PIECE. The strong horizontal beam of the windlass, supported at the ends by iron spindles in the windlass-bitts.

MAIN-PIECE of the Rudder. The rudder-stock, or piece which is connected by the rudder-bands to the stern-post.

MAIN-POST. The stern-post, as distinguished from the false-post and inner-post.

MAIN ROYAL-MAST. That above the main topgallant-mast.

MAIN-SAIL. This, in a square-rigged vessel, is distinguished by the so-termed square main-sail; in a fore-and-aft rigged vessel it obtains the name of boom main-sail. Brigs carry both.

MAIN-SAIL HAUL! The order given to haul the after-yards round when the ship is nearly head to wind in tacking.