What is the name of a beam that carries the weight of another beam?

A beam that carries the weight of another beam is known as a girder. The girder serves as a primary structural element in buildings, supporting the loads from the beams that rest upon it. It's crucial in distributing weight to vertical supports, such as columns or walls, thereby maintaining the stability and integrity of a structure.

In contrast, a ledger is typically used to support the ends of joists or other beams rather than carrying the weight of another beam. A rafter is a sloped beam that supports the roof of a structure, and a spar is a term more commonly associated with nautical contexts, referring to a pole or beam used in shipbuilding, rather than architecture. Understanding the role of these different structural components is key to recognizing their specific functions in supporting and distributing loads within a building.