mast
n//mæst//mast
(nautical, communications, aviation) A tall, slim post or tower, usually tapering upward, used to support, for example, sails or observation platforms on a ship, the main rotor of a helicopter, flags, floodlights, meteorological instruments, or communications equipment, such as an aerial, usually supported by guy-wires (except in the case of a helicopter). [from 9th c.]