In aviation terms, what does "weight" refer to?

In aviation, "weight" specifically refers to the force acting downward due to gravity. It is a crucial concept because it directly affects an aircraft's performance, including takeoff, landing, and overall flight characteristics. Weight is not merely the mass of the aircraft but rather the gravitational force acting on that mass. This force is a primary factor in determining how much lift the wings need to generate for the aircraft to become airborne and maintain flight.

While the total mass of the aircraft is an important factor, it is the weight that is used in flight dynamics and performance calculations. Similarly, the upward force on the aircraft, commonly referred to as lift, is a separate concept that must counteract weight for an aircraft to ascend. The load capacity of the aircraft pertains to the maximum weight it can safely carry but does not define "weight" itself. Understanding this distinction is critical for pilots and aviation professionals in managing safe operations.