A square nut is a type of fastener that is designed to be used with a bolt or screw. It is called a square nut because of its square shape, which makes it easier to grip with a wrench or pliers. However, there are several other names for this type of nut, including four-sided nut, quad nut, and box nut. These synonyms all refer to the same type of nut, but some people may prefer one name over the others depending on their personal preference or industry terminology. Regardless of what you call it, the square nut is an essential tool for many different types of construction and manufacturing projects.