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.
b.
any of a number of individual spars composing such a structure, as a topmast supported on trestletrees at the head of a lower mast.
c.
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.
2.
Also called pillar.the upright support of a jib crane.
3.
any upright pole, as a support for an aerial, a post in certain cranes, etc.
verb (used with object)
4.
to provide with a mast or masts.
Idiom
5.
before the mast, Nautical. as an unlicensed sailor: He served several years before the mast.
Origin: before 900; Middle English; Old English mæst; cognate with German Mast; akin to Latin mālus pole