Page "Weight" Paragraph 3

In everyday usage the term " weight " is commonly used to mean mass, which scientifically is an entirely different concept.

On the surface of the Earth, the acceleration due to gravity ( the " strength of gravity ") is approximately constant ; this means that the ratio of the weight force of a motionless object on the surface of the Earth to its mass is almost independent of its location, so that an object's weight force can stand as a proxy for its mass, and vice versa.