A headsail of a sailing vessel is any sail set forward of the foremost mast. The most common headsails are staysails, a term that includes jibs and the larger genoa. Other headsails are set independently of any forestays, such as the spinnaker. Some headsails can only be flown on specific points of sail, such as the spinnaker, which is only flown ... Found on http://en.wikipedia.org/wiki/Headsail