The top and bottom horizontal member of a truss is called?

The correct answer identifies that the top and bottom horizontal members of a truss are known as the "chords." In a truss system, these horizontal members are critical structural elements that help to maintain the integrity and shape of the truss. The upper chord typically bears the load from above, while the lower chord serves to resist tension and hold the truss shape.

Understanding the role of chords in truss design is fundamental to structural engineering. They distribute loads efficiently and allow for the lightweight construction of roofs and bridges.

Other terms listed refer to different structural components. A beam generally denotes a horizontal structural element that supports vertical loads, while a post is a vertical member supporting horizontal beams. Rafters refer specifically to sloped members that support the roof of a building, rather than being the horizontal components found in a truss design.