Nautical A wooden or metal pole, such as a boom, yard, or bowsprit, used to support sails and rigging. A usually metal pole used as part of a crane or derrick. A main structural member in an airplane wing or a tail assembly that runs from tip to tip or from root to tip. To supply with spars. Archaic To fasten with a bolt. To fight with an opponent in a short bout or practice session, as in boxing or the martial arts. To make boxing or fighting motions without hitting one's opponent. To bandy words about in argument; dispute. To fight by striking with the feet and spurs. Used of gamecocks. A motion of attack or defense in boxing. A sparring match. A nonmetallic, readily cleavable, translucent or transparent light-colored mineral with a shiny luster, such as feldspar.