time dilation

time dilation

n.

The relativistic slowing of a clock that moves with respect to a stationary observer. Also called time dilatation.

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time dilation

The relativistic effect of the slowing of a clock with respect to an observer. In Special Relativity, a clock moving with respect to an observer appears to run more slowly than to an observer moving with the clock. In General Relativity, time dilation is also caused by gravity; clocks on the earth's surface, for example, run more slowly than clocks at high altitudes, where gravitational forces are weaker.