# rel|a|tiv|i|ty

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rel|a|tiv|i|ty
rel|a|tiv|i|ty «REHL uh TIHV uh tee», noun.
1. the condition of being relative.
2. Philosophy. existence only in relation to the human mind.
3. Physics. the character of being relative rather than absolute, as ascribed to motion or velocity.
4. a) a theory dealing with the physical laws which govern time, space, mass, motion, and gravitation, expressed in certain equations by Albert Einstein; special theory of relativity. According to it, the only velocity we can measure is velocity relative to some body, for if two systems are moving uniformly in relation to each other, it is impossible to determine anything about their motion except that it is relative, and the velocity of light is constant, independent of either the velocity of its source or an observer. Thus it can be mathematically derived that mass and energy are interchangeable, as expressed in the equation E = mc2, where c = the velocity of light; that a moving object appears to be shortened in the direction of the motion to an observer at rest; that a clock in motion appears to run slower than a stationary clock to an observer at rest; and that the mass of an object increases with its velocity. »

One of the fundamental postulates of relativity is that the velocity of light is the same in all circumstances, even when the source and the observer are in relative motion (W. H. Marshall).

b) an extension of this theory, dealing with the equivalence of gravitational and inertial forces; general theory of relativity.

Useful english dictionary. 2012.

### Look at other dictionaries:

• rel|uc|tiv|i|ty — «REHL uhk TIHV uh tee», noun. Physics. the ratio of the intensity of the magnetic field to the magnetic induction of a substance; the reciprocal of permeability …   Useful english dictionary

• rel·a·tiv·i·ty — /ˌrɛləˈtıvəti/ noun [noncount] physics : a theory developed by Albert Einstein which says that the way that anything except light moves through time and space depends on the position and movement of someone who is watching …   Useful english dictionary

• rel|a|tiv|ism — «REHL uh tuh VIHZ uhm», noun. the philosophical doctrine of the relativity of knowledge, truth, or certainty …   Useful english dictionary

• rel|a|tiv|is|ti|cal|ly — «REHL uh tuh VIHS tuh klee», adverb. 1. in a relativistic manner: »Most of the mass of the three quarks in a proton is relativistically converted into the tremendous energy that binds them together (Time). 2. from a relativistic point of view:… …   Useful english dictionary

• rel|a|tiv|is|tic — «REHL uh tuh VIHS tihk», adjective. 1. of or having to do with relativity: »Relativistic phenomena generally cause a lot of intellectual difficulties for the non scientist (Atlantic). 2. of or having to do with relativism or relativists. 3.… …   Useful english dictionary

• rel|a|tiv|ist — «REHL uh tuh vihst», noun, adjective. –n. 1. a person who believes in the theory of relativity: »The now dormant relativists may awaken to brave new concepts that will reorient us in the universe of matter and ideas (Harlow Shapley). 2. a person… …   Useful english dictionary

• rel|a|tiv|ize — «REHL uh tuh vyz», transitive verb, ized, iz|ing. to make relative: »Recognition of the reality of evil necessarily relativizes the good (Carl G. Jung) …   Useful english dictionary

• rel·a·tiv·ism — …   Useful english dictionary

• cor|rel|a|tiv|i|ty — «kuh REHL uh TIHV uh tee», noun. correlative quality; interconnection …   Useful english dictionary

• tiv — ab·sorp·tiv·i·ty; ac·tiv·ism; ac·tiv·i·ty; ac·tiv·ize; ad·di·tiv·i·ty; ad·jec·tiv·ize; af·fec·tiv·i·ty; al·ter·na·tiv·i·ty; ca·pac·i·tiv·i·ty; cap·tiv·i·ty; cog·ni·tiv·ism; cog·ni·tiv·ist; col·lec·tiv·ism; col·lec·tiv·i·ty; col·lec·tiv·ize;… …   English syllables