# 18: The Catenary

- Page ID
- 7050

If a flexible chain or rope is loosely hung between two fixed points, it hangs in a curve that looks a little like a parabola, but in fact is not quite a parabola; it is a curve called a *catenary*, which is a word derived from the Latin *catena*, a chain.

- 18.1: Introduction
- If a flexible chain or rope is loosely hung between two fixed points, it hangs in a curve that looks a little like a parabola, but in fact is not quite a parabola; it is a curve called a catenary, which is a word derived from the Latin catena, a chain.

- 18.2: The Intrinsic Equation to the Catenary
- The intrinsic equation of the catenary is derived from considerations of a chain hanging from two fixed points.

*Thumbnail: The Saint Louis arch is a weighted catenary—its legs are wider than its upper section. Image used with permission (CC BY 2.0; *