载荷 is a technical term for 'load' — the weight, force, or stress that a structure, machine, or system must support. You'll see it in engineering, physics, and logistics contexts (e.g. 结构载荷 'structural load', 额定载荷 'rated load'). It's almost identical in meaning to 负载 (fùzài) but 载荷 is more common in formal/technical writing. Unlike the everyday word 重量 (weight), 载荷 emphasizes the bearing capacity or designed limit.