Topgallant sail
The topgallant sail (also pronounced as "t'garns'l") was the upper most, or second upper most sail (below the royal, if present), attached to the yardarm of a sailing vessel's mast.

During the promotion of Worf aboard the holodeck recreation of the 19th century  , Commander William T. Riker ordered "all hands" to "make sail" calling for the t'garns'ls and s to be unfurled first, and to stand by on the s. ()

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Propulsion technology