The forestaysail is a triangular sail that is usually attached to the forestay of a sailing vessel. Though it is a specific term for this type of sail, there are a few synonyms one could use to describe it. One synonym for forestaysail is jib, which is a sail that is usually smaller than the main sail and is positioned towards the front of the vessel. Another synonym for forestaysail is headsail, which is a term that describes any sail that is located forward of the mainsail. Finally, a third synonym for forestaysail is staysail, which refers to any sail that is attached to a stay or a mast.