Question

what is a good defination of relativity​

Answer 1

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Einstein’s belief that all movement is affected by space, light, time and gravity

(भौतिक विज्ञान में) सापेक्षता का सिद्घांत, सापेक्षवाद (आइंस्‍टाइन की मान्‍यता कि सब प्रकार की गति स्‍थान, प्रकाश, समय और गुरुत्‍वाकर्षण से प्रभावित होती है अर्थात तत्‍सापेक्ष होती है)

Answer 2

Relativity is the word for how things only have importance in relation to other things.

In physics, relativity refers to Einstein's theory that time and space are not absolute.

For example, time partially depends on our perceptions of it: time is relative.

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