big bang theory

noun

: a theory in astronomy: the universe originated billions of years ago in a rapid expansion from a single point of nearly infinite energy density compare steady state theory

Examples of big bang theory in a Sentence

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Ten years ago, the Large Hadron Collider, the world’s largest and most powerful particle accelerator, found the Higgs boson particle, helping to explain the big bang theory and how the universe was formed. Nate Trela, USA TODAY, 20 Sep. 2017 Science has already yielded lots of answers, including the theory of evolution, the genetic code, quantum mechanics, general relativity and the big bang theory. John Horgan, Scientific American, 7 Aug. 2021

Word History

First Known Use

1955, in the meaning defined above

Time Traveler
The first known use of big bang theory was in 1955

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Cite this Entry

“Big bang theory.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/big%20bang%20theory. Accessed 26 Mar. 2025.

Kids Definition

big bang theory

noun
: a theory that the universe was created billions of years ago as a result of a giant explosion
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