gravity

American  

[grav-i-tee] / ˈgræv ɪ ti /

noun

plural

gravities

1. the force of attraction by which terrestrial bodies tend to fall toward the center of the earth.

2. heaviness or weight.

3. gravitation in general.

4. acceleration of gravity.

5. a unit of acceleration equal to the acceleration of gravity. g

6. serious or critical nature.

   He seemed to ignore the gravity of his illness.

   Synonyms:

   import, emergency, danger, seriousness

7. serious or dignified behavior; dignity; solemnity.

   to preserve one's gravity in the midst of chaos.

8. lowness in pitch, as of sounds.

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gravity British  

/ ˈɡrævɪtɪ /

noun

1. the force of attraction that moves or tends to move bodies towards the centre of a celestial body, such as the earth or moon

2. the property of being heavy or having weight See also specific gravity centre of gravity

3. another name for gravitation

4. seriousness or importance, esp as a consequence of an action or opinion

5. manner or conduct that is solemn or dignified

6. lowness in pitch

7. (modifier) of or relating to gravity or gravitation or their effects

   gravity wave

   gravity feed

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gravity Scientific  

/ grăv′ĭ-tē /

1. The fundamental force of attraction that all objects with mass have for each other. Like the electromagnetic force, gravity has effectively infinite range and obeys the inverse-square law. At the atomic level, where masses are very small, the force of gravity is negligible, but for objects that have very large masses such as planets, stars, and galaxies, gravity is a predominant force, and it plays an important role in theories of the structure of the universe. Gravity is believed to be mediated by the graviton, although the graviton has yet to be isolated by experiment. Gravity is weaker than the strong force, the electromagnetic force, and the weak force.

2. Also called gravitation

3. See more at acceleration relativity

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gravity Cultural  

1. Another term for gravitation, especially as it affects objects near the surface of the Earth.

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Closer Look

With his law of universal gravitation, Sir Isaac Newton described gravity as the mutual attraction between any two bodies in the universe. He developed an equation describing an instantaneous gravitational effect that any two objects, no matter how far apart or how small, exert on each other. These effects diminish as the distance between the objects gets larger and as the masses of the objects get smaller. His theory explained both the trajectory of a falling apple and the motion of the planets—hitherto completely unconnected phenomena—using the same equations. Albert Einstein developed the first revision of these ideas. Einstein needed to extend his theory of Special Relativity to be able to understand cases in which bodies were subject to forces and acceleration, as in the case of gravity. According to Special Relativity, however, the instantaneous gravitational effects in Newton's theory would not be possible, for to act instantaneously, gravity would have to travel at infinite velocities, faster than the speed of light, the upper limit of velocity in Special Relativity. To overcome these inconsistencies, Einstein developed the theory of General Relativity, which connected gravity, mass, and acceleration in a new manner. Imagine, he said, an astronaut standing in a stationary rocket on the Earth. Because of the Earth's gravity, his feet are pressed against the rocket's floor with a force equal to his weight. Now imagine him in the same rocket, this time accelerating in outer space, far from any significant gravity. The accelerating rocket pushing against his feet creates a force indistinguishable from that of a gravitational field. Developing this principle of equivalence, Einstein showed that mass itself forms curves in space and time and that the effects of gravity are related to the trajectories taken by objects—even objects without mass, such as light. Whether gravity can be united with the other fundamental forces understood in quantum mechanics remains unclear.

Other Word Forms

• nongravity noun

Etymology

Origin of gravity

First recorded in 1500–10; from Latin gravitāt-, stem of gravitās “heaviness”; equivalent to grave ² + -ity

Example Sentences

In certain applications, known as gravimeters, scientists focus on how gravity changes across space.

From Science Daily

I'm told the judgement was more simple: it was categorically the right thing to do, the prime minister concluded, given the gravity of offence the president had caused.

From BBC

Researchers will also need to refine their theoretical models to better explain how gravity, radiation, and stellar winds interact to shape these escaping atmospheres.

From Science Daily

Cohesion is often referred to as the strategic center of gravity for NATO—its ability to act as one despite being made up of 32 countries.

From The Wall Street Journal

This phenomenon arises from a counterintuitive property of gravity, where systems bound by gravity become hotter as they lose energy rather than cooling down.

From Science Daily

Related Words

• consequence
• severity
• significance
• solemnity
• urgency