Casually, gravity and gravitation are used as synonyms. Strictly speaking, however, gravity is the force which causes the acceleration of free fall on the Earth surface, which is the resultant of gravitation and the centrifugal pseudo-force associated with the Earth's rotation.
In a general sense, gravity means seriousness, of a person or situation. Thus, a grave person is not smiling. The opposite sense of gravity is levity, or wit and humor.
In chemistry, gravity can refer to the density of a fluid, particularly a fuel.
