WordNet (r) 3.0 (2006):

gravitational force
    n 1: (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 [syn: gravity, gravitation,
         gravitational attraction, gravitational force]