gaff topsail

noun Nautical.
  1. Also called fore-and-aft topsail. a jib-headed fore-and-aft sail set above a gaff.
  2. a quadrilateral fore-and-aft sail set above the spanker of a bark, between the gaff of the spanker and an upper gaff.

Origin of gaff topsail

First recorded in 1785–95
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018