What is defined as a loose or slack part of a rope between two ends?

The term that describes a loose or slack part of a rope between two ends is known as a bight. A bight is formed when there is a length of rope that has not been tautened; it creates a curve or bend in the rope. This is an important concept in rigging and knot-tying, as understanding how to identify and utilize a bight can influence the security and effectiveness of various knots and harnesses.

While the other terms relate to different aspects of rope work, they do not specifically define a loose part of a rope. A loop refers to a circular or curved section made in the rope, which may or may not be under tension. The term lead is generally used to refer to the direction of a rope's path or a specific length of rope used in a certain application, and end line is more related to the terminus of the rope rather than a slack section. Understanding the definition of a bight is crucial for anyone working with ropes in various applications, impacting safety and efficiency.