<p><strong>Noun</strong></p><ul><li>Nautical: a spar or structure rising above the hull and upper portions of a ship or boat to hold sails, spars, rigging, booms, signals, etc., at some point on the fore-and-aft line, as a foremast or mainmast.</li><li>Any of a number of individual spars composing such a structure, as a topmast supported on trestletrees at the head of a lower mast.</li><li>Any of various portions of a single spar that are beside particular sails, as a top-gallant mast and royal mast formed as a single spar.</li><li>Also called pillar: the upright support of a jib crane.</li><li>Any upright pole, as a support for an aerial, a post in certain cranes, etc.</li></ul><p><strong>Verb</strong></p><ul><li>(used with object) to provide with a mast or masts.</li></ul>