What component is located over the fireplace opening to support the masonry above?

The component located over the fireplace opening that supports the masonry above is known as a lintel. A lintel is a horizontal structural element designed to carry the load from the masonry or other structural materials above the fireplace, transferring that weight to the sides of the opening. This is crucial in maintaining the stability of the wall and preventing sagging or cracking.

Lintels can be made from various materials, such as steel, wood, or concrete, and they serve as a vital support mechanism when the structure spans an opening like a fireplace. This allows for the design and installation of fireplaces without compromising the overall integrity of the wall.

In contrast, while a flue relates to the channel for exhaust gases from the fireplace, it does not provide structural support. A beam is a broader term for any structural element that supports loads but is not specific to fireplace openings. A brick arch can also distribute weight but is not typically used above a fireplace opening in the conventional sense. Thus, the lintel is the correct answer as it directly serves the purpose of supporting the masonry over the fireplace.