relativity
noun
rel·a·tiv·i·ty
ˌre-lə-ˈti-və-tē 
plural relativities
1
a
: the quality or state of being relative
b
: something that is relative
2
: the state of being dependent for existence on or determined in nature, value, or quality by relation to something else
3
a
: a theory which is based on the two postulates (1) that the speed of light in a vacuum is constant and independent of the source or observer and (2) that the mathematical forms of the laws of physics are invariant in all inertial systems and which leads to the assertion of the equivalence of mass and energy and of change in mass, dimension, and time with increased velocity
called also special relativity, special theory of relativity
b
: an extension of the theory to include gravitation and related acceleration phenomena
called also general relativity, general theory of relativity
Examples of relativity in a Sentence
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In fact, the mathematics underpinning Albert Einstein's theories of relativity offer up possibilities via the likes of wormholes and curved spacetime that might allow someone — or more likely something — to make a journey back into the past.
—
Richard Edwards, Space.com, 17 Mar. 2026
While this may confine a human’s dream of immortality to solutions that rely on technological enhancements, bio-hacking your body, or science-fiction level technology that relies on novel physical laws and/or phenomena, there’s still plenty that relativity has to say about living forever.
—Big Think, 12 Mar. 2026
It’s brilliantly put for an American slogan of that post‑Einsteinian understanding of relativity, and how perception of the phenomenal world depends on the measuring instrument and the perceiver.
—Literary Hub, 27 Feb. 2026
Feeney’s book features multiple narrators, but relativity is not an idea the series bothers to develop.
—Television Critic, Los Angeles Times, 8 Jan. 2026
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Richard Edwards, Space.com, 17 Mar. 2026
While this may confine a human’s dream of immortality to solutions that rely on technological enhancements, bio-hacking your body, or science-fiction level technology that relies on novel physical laws and/or phenomena, there’s still plenty that relativity has to say about living forever.
—Big Think, 12 Mar. 2026
It’s brilliantly put for an American slogan of that post‑Einsteinian understanding of relativity, and how perception of the phenomenal world depends on the measuring instrument and the perceiver.
—Literary Hub, 27 Feb. 2026
Feeney’s book features multiple narrators, but relativity is not an idea the series bothers to develop.
—Television Critic, Los Angeles Times, 8 Jan. 2026
See All Example Sentences for relativity
Cite this Entry
“Relativity.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/relativity. Accessed 29 Mar. 2026.
Copy CitationKids Definition
relativity
noun
rel·a·tiv·i·ty
ˌrel-ə-ˈtiv-ət-ē
plural relativities
1
: the quality or state of being relative
especially
: dependence on something else
2
a
: a theory in physics that considers mass and energy to be equal and that states that a moving object will experience changes in mass, size, and time which are related to its speed and are not noticeable except at speeds approaching that of light
b
: an extension of relativity theory to include gravity and its related acceleration effects
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