What is the term that describes the external force acting on a structure?

The term that describes the external force acting on a structure is a load. In structural engineering and building construction, a load refers to any external force or weight that is applied to a structural element, which can include live loads (like people and furniture), dead loads (such as the weight of the structure itself), environmental loads (such as wind or snow), and dynamic loads (like those caused by movement or impact). Understanding loads is crucial in designing structures that can safely support these forces without experiencing failure.

Other terms, while related, have more specific meanings. A vector represents a quantity that has both magnitude and direction, which can be used to analyze loads but does not specifically define the external forces themselves. Stress, on the other hand, refers to the internal response of a material to a load, expressed as force per unit area, and thus is more about the effects of the loads on materials rather than the loads themselves. Similarly, while force is a more general term that encompasses various influences acting on an object, in the context of structural engineering, the term 'load' specifically captures the essence of external forces as they relate to a structure's integrity and safety.