quan·​tum | \ ˈkwän-təm How to pronounce quantum (audio) \
plural quanta\ ˈkwän-​tə How to pronounce quantum (audio) \

Definition of quantum

 (Entry 1 of 2)

b : portion, part
c : gross quantity : bulk
2a : any of the very small increments or parcels into which many forms of energy are subdivided
b : any of the small subdivisions of a quantized physical magnitude (such as magnetic moment)



Definition of quantum (Entry 2 of 2)

1 : large, significant a quantum improvement
2 : of, relating to, or employing the principles of quantum mechanics quantum physics

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Synonyms for quantum

Synonyms: Noun

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Examples of quantum in a Sentence

Noun the sum of human knowledge is now so immense that even a highly educated person can hope to absorb only a tiny quantum of it
Recent Examples on the Web: Noun Prioritizing breakthrough technologies like artificial intelligence and quantum computing, meanwhile, would go a long way toward sustaining American leadership in the industries of the future. Star Tribune, "Biden should prioritize research and development," 26 Jan. 2021 Both companies published more than 1,500 patent applications last year for innovations in the fields of digital information transfer, machine learning, quantum computing and neural networks, according to IFI Claims. oregonlive, "Intel stays in top 10 for patent applications in 2020; Amazon falls," 16 Jan. 2021 After all, physicists arrived at the Schrödinger equation and other canonical quantum formulas only haltingly, after many false steps. John Horgan, Scientific American, "Is the Schrödinger Equation True?," 7 Jan. 2021 The Chinese quantum supercomputer was built to perform a single, specific task and cannot be programmed to do anything else. Naomi Xu Elegant, Fortune, "Joe Biden underestimated China’s ability to innovate before. He shouldn’t repeat that mistake," 17 Dec. 2020 The defense bill also includes provisions that would require the government to come up with a plan to spend an additional $10 billion per year on advanced technologies such as AI, quantum computing, and 5G wireless services by 2025. Will Knight, Wired, "Trump Could Torpedo a Bill to Boost Funding for AI," 16 Dec. 2020 Physicists have confirmed the existence of an extraordinary, flat particle that could be the key that unlocks quantum computing. Caroline Delbert, Popular Mechanics, "This Incredible Particle Only Arises in Two Dimensions," 18 Dec. 2020 The star of the show is a pulsing, bright-gold quantum computer. Wired Staff, Wired, "The Best Pop Culture That Got Us Through 2020," 16 Dec. 2020 Whereas the quantum computer used in Google's experiment can be adapted to other purposes, the Chinese rig is rigid and inflexible. Robert Hackett, Fortune, "Google and China duke it out over ‘quantum supremacy’," 8 Dec. 2020 Recent Examples on the Web: Adjective Stefan Hollands of the University of Leipzig in Germany and his colleagues take issue with applying the regular quantum equations to curved spacetime, saying they were designed with flat space in mind. Clara Moskowitz, Scientific American, "The Cosmological Constant Is Physics’ Most Embarrassing Problem," 1 Feb. 2021 The system transitions by passing through a mixture of the excited state and ground state, a quantum phenomenon known as superposition. Eleni Petrakou, Scientific American, "New Views of Quantum Jumps Challenge Core Tenets of Physics," 29 Dec. 2020 The Biden administration is expected to invest more money in AI and quantum information science, in part because overall spending on research and development is expected to be higher, said Robert D. Atkinson, president of the ITIF. Sara Castellanos, WSJ, "AI, Quantum R&D Funding to Remain a Priority Under Biden," 9 Nov. 2020 Scientists say practical, widespread applications for quantum computers are likely years away. Yaacov Benmeleh, Fortune, "Amazon is laying the groundwork for its own quantum computer," 1 Dec. 2020 Computing giants like Google and IBM, as well as a flock of smaller competitors, are building and refining quantum hardware. The Economist, "Wall Street’s latest shiny new thing: quantum computing," 16 Dec. 2020 Indeed, some quantum manifestations still confound physicists. Michael Hiltzik, Los Angeles Times, "Column: Why I never ‘agree to disagree’ — I just tell you you’re wrong," 22 Dec. 2020 The goal of studying black holes is usually to marry classical and quantum physics. Caroline Delbert, Popular Mechanics, "New Experiment Utterly Alters What We Know About Black Holes," 14 Dec. 2020 Boson sampling is a quantum computer that solves itself by being the distribution of photons. Daniel Garisto, Scientific American, "Light-based Quantum Computer Exceeds Fastest Classical Supercomputers," 3 Dec. 2020

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

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First Known Use of quantum


1567, in the meaning defined at sense 1a


1942, in the meaning defined at sense 1

History and Etymology for quantum


Latin, neuter of quantus how much

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Time Traveler for quantum

Time Traveler

The first known use of quantum was in 1567

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Statistics for quantum

Last Updated

7 Feb 2021

Cite this Entry

“Quantum.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/quantum. Accessed 28 Feb. 2021.

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More Definitions for quantum



English Language Learners Definition of quantum

 (Entry 1 of 2)

physics : the smallest amount of many forms of energy (such as light)



English Language Learners Definition of quantum (Entry 2 of 2)

physics : of, relating to, or using the principles of quantum theory


quan·​tum | \ ˈkwänt-əm How to pronounce quantum (audio) \
plural quanta\ ˈkwänt-​ə How to pronounce quantum (audio) \

Medical Definition of quantum

1 : one of the very small increments or parcels into which many forms of energy are subdivided a molecule of rhodopsin in the human eye can cause a response to a single quantum of light
2 : one of the small molecular packets of a neurotransmitter (as acetylcholine) released into the synaptic cleft in the transmission of a nerve impulse across a synapse

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