- To fold or roll a sail on its yard or boom.
Probably earlier than the 17th century. Earlier terms were furdle and farthel. From Old French, ferlier, meaning to bind. Possible origins in Arabic, as well.
Pretty self-explanatory. There are actually different methods of furling and it’s also done to prevent damage to the sail. Before more mechanical or automatic means were developed, sails had to furled by hand.
Rogers, J.G. (1985). Origins of Sea Terms. Mystic Seaport Museum.