Yardarm
A yardarm was the outer most part of the main horizontal spar that a sail was suspended from (the yard) on a sailing vessel. 

Upon viewing the "hole in space" in 2365, Commander William T. Riker was reminded of his course in ancient history at Starfleet Academy, specifically "about the time men still believed the Earth was flat," when it was believed "that if a ship sailed too far out into the ocean, it would fall off the edge of the world." Captain Jean-Luc Picard continued recalling the legend adding, "It's even said that crews threatened to hang their captain from the yardarm if he refused to turn back." ()

During the promotion of Worf aboard the holodeck recreation of the 19th century  , Riker pointed out the ship's last yardarm while he explained to Geordi La Forge the location of the ship's stunsail. ()

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Transportation technology