What does weight measure?

Weight specifically measures the force exerted on an object due to gravity. This force depends on both the mass of the object and the acceleration due to gravity, which varies slightly depending on location (e.g., whether you're at sea level or on a mountain). Though mass is a measure of the amount of matter in an object and remains constant regardless of the object's location, weight changes with the gravitational force acting on that mass.

The correct understanding of weight as the gravitational force is essential in physics, as it helps explain how objects behave under different conditions, such as on Earth versus the Moon, where gravitational attraction is weaker. This distinction highlights why the other options do not describe weight accurately; for instance, while mass is a measure of matter, it does not change with gravity and thus is not considered weight.