[n] (physics) the force of attraction between all masses in the universe; especially the attraction of the earth's mass for bodies near its surface; "the more remote the body the less the gravity"; "the gravitation between two bodies is proportional to the product of their masses and inversely proportional to the square of the distance between them"; "gravitation cannot be held responsible for people falling in love" -Albert Einstein
"How Paper Money is Made
The manufacture of banknotes plays an important role in allowing them to be used as money with confidence. High quality paper is specially made for durability and security. Designs are chosen to make the notes recognisable as national currency, then reproduced by first-class engraving and printing. New security devices are created by computer graphics and advanced technology. The threat of forgery is a constant problem, despite severe penalties. However, this encourages continuing research into improved production methods. "