What is the term used to describe a bend in a rope to form a knot?

The term that describes a bend in a rope to form a knot is a "bight." A bight refers specifically to a section of rope that has been bent into a U-shape, creating a loop. This formation is an essential part of knot-tying as it allows the rope to be manipulated in a way that can secure different types of knots. In various knot-tying techniques, forming a bight is the foundational step before other maneuvers can be executed to create the complete knot.

The other terms have specific meanings that do not accurately reflect the original question's context. For instance, a "loop" generally refers to a closed curve made from the rope but does not emphasize the bending aspect as a bight does. A "hitch," on the other hand, is a type of knot used to attach a rope to an object, and it doesn't pertain to just bending the rope itself. A "knob" does not refer to a knot or any component of knot-tying and relates more to a shape or object rather than a technique used in working with rope. The clear definition of a bight in knot-tying makes it the correct answer in this context.