rel·​a·​tiv·​i·​ty | \ ˌre-lə-ˈti-və-tē How to pronounce relativity (audio) \
plural relativities

Definition of relativity

1a : 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
3a : 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

Recent Examples on the Web This is also the speed that any form of pure radiation, such as gravitational radiation, must travel at, and also the speed, under the laws of relativity, that any massless particle must travel at. Ethan Siegel, Forbes, "There’s Only One Way To Beat The Speed Of Light," 12 May 2021 Light and shadow intermix and surround the objects on the table, rearranging the elements of reality into a new visual expression arguably inspired by scientific theories like Planck’s quantum theory and Einstein’s theory of relativity. John Zotos, Dallas News, "DMA exhibition reveals why Juan Gris is more important than you thought," 7 May 2021 Proust’s celebrated account of time’s relativity, dancing above or outside experience, though persuasively detailed, is not terribly original. Adam Gopnik, The New Yorker, "What We Find When We Get Lost in Proust," 3 May 2021 And dark matter exists in this larger context of space-time, which is how Einstein's theory of relativity requires us to think of space and time, as existing in relationship with each other. Lisa Selin Davis, CNN, "Black physicist rethinks the 'dark' in dark matter," 2 May 2021 According to the equations of relativity, information that travels past the event horizon into a black hole is forever lost—erased, as far as any outside observer is concerned. James Gleick, The New York Review of Books, "Eclipsed by Fame," 13 Apr. 2021 General relativity also describes how mass and energy warp spacetime – hefty objects like stars and black holes curve spacetime around them. Mario Borunda, The Conversation, "Warp drives: Physicists give chances of faster–than–light space travel a boost," 23 Apr. 2021 Quantum mechanics and relativity demand that the muon have a certain basic magnetism. Adrian Cho, Science | AAAS, "Fresh calculation of obscure particle's magnetism could dim hopes for new physics," 14 Apr. 2021 While most of cosmology was built on a foundation of Einsteinian relativity, Hawking was also considering the role of quantum mechanics, which governs behavior at the smallest scales. James Gleick, The New York Review of Books, "Eclipsed by Fame," 13 Apr. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'relativity.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of relativity

circa 1834, in the meaning defined at sense 1a

Keep scrolling for more

Learn More about relativity

Time Traveler for relativity

Time Traveler

The first known use of relativity was circa 1834

See more words from the same year

Statistics for relativity

Last Updated

17 May 2021

Cite this Entry

“Relativity.” Dictionary, Merriam-Webster, Accessed 18 May. 2021.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

Keep scrolling for more

More Definitions for relativity



English Language Learners Definition of relativity

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

Comments on relativity

What made you want to look up relativity? Please tell us where you read or heard it (including the quote, if possible).


Test Your Vocabulary

Words Used by Nabokov Quiz

  • image1676440788
  • Choose the best definition or synonym for the word in bold: "There are some eructations that sound like cheers—at least, mine did." Lolita
Name That Thing

Test your visual vocabulary with our 10-question challenge!


Anagram puzzles meet word search.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!