The reef knot, also known as the square knot, is a popular type of knot that is used for various purposes. It is a simple and versatile knot that is easy to tie, making it a favorite among sailors, climbers, and anglers. However, there are also other synonyms for the reef knot that are commonly used. Some of these synonyms include the flat knot, Josephine knot, and double knot. These knots are also used for similar purposes, but may have slightly different tying techniques or variations in their appearance. Knowing these synonyms can be helpful when searching for knot tying instructions or when communicating with other knot enthusiasts.