gravity

n. attractive force which causes all bodies to move toward the center of the earth; weight, heaviness; severity; seriousness; solemnity

Gravitation is a natural phenomenon by which all objects with mass attract each other. In everyday life, gravitation is most familiar as the agency that endows objects with weight. It is responsible for keeping the Earth and the other planets in their orbits around the Sun; for keeping the Moon in its orbit around the Earth, for the formation of tides; for convection (by which hot fluids rise); for heating the interiors of forming stars and planets to very high temperatures; and for various other phenomena that we observe. Gravitation is also the reason for the very existence of the Earth, the Sun, and most macroscopic objects in the universe; without it, matter would not have coalesced into these large masses and life, as we know it, would not exist.
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(a.)
The tendency of a mass of matter toward a center of attraction; esp., the tendency of a body toward the center of the earth; terrestrial gravitation.
  

(a.)
The state of having weight; beaviness; as, the gravity of lead.
  

(a.)
Sobriety of character or demeanor.
  

(a.)
Lowness of tone; -- opposed to acuteness.
  

(a.)
Importance, significance, dignity, etc; hence, seriousness; enormity; as, the gravity of an offense.
  

One of the forces of nature. It is an attractive force exerted between two or more particles all of which have mass. It was discovered by Isaac Newton in c1690, who stated the law of gravity : 'Every mass in the Universe attracts every other with a force proportional to the product of their masses and inversely proportional to their distance of separation squared'. Despite being the weakest force of nature, gravity shapes the universe on the largest of scales. It is long range, i.e. it extends from a mass to infinity. It is an unsaturated force, that is, the more masses that aggregate together the greater the force (unlike the short range forces in a drop of liquid that remain unchanged no matter how large the drop). Unlike electromagnetism, gravity only attracts: it does not repel. General relativity is the best theory to explain the effects of gravity.

The force of attraction exerted by one body in the universe on another. Gravity is directly proportional to the product of the masses of the two attracted bodies. 2. The force of attraction exerted by the Earth on bodies on or near its surface, tending to pull them toward the Earth's center.