A female threaded hexagonal-shaped fastener is referred to as what?

The correct answer is the term for a female threaded hexagonal-shaped fastener, which is commonly referred to as a nut. Nuts are specifically designed to work with bolts, providing the female counterpart to secure them together. The hexagonal shape allows for easy handling with tools such as wrenches, facilitating the tightening and loosening processes.

In terms of function, nuts are used to fasten components together in a reliable manner, creating a connection that can withstand various forces and stresses in engineering applications. Their threading allows them to engage securely with the male threads of a bolt, thus forming a secure assembly. While washers, studs, and bolts serve different purposes and have different designs, the unique role of a nut as a female threaded component is what distinguishes it and makes it the appropriate answer here.