lugsail

noun

1. A quadrilateral sail bent upon a yard that crosses the mast obliquely; a lug.

   “1885, Alexander Stewart, ’Twixt Ben Nevis and Glencoe: The Natural History, Legends, and Folk-Lore of the West Highlands, Edinburgh: William Paterson, Chapter 46, p. 336, It was a bright afternoon, with just enough wind over the quarter to set our lugsail well abulge, and make our little “Penguin” dance merrily over the rippling wavelets.”