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

amount, measure, quantity, volume

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Examples of quantum in a Sentence


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

Little’s priorities are neither a big surprise nor a quantum shift. Kevin Richert, idahostatesman, "Little’s K-12 task force has two big priorities: literacy and student life after high school," 4 June 2019 The Energy Department’s Office of Science saw its quantum funding roughly double, to $120 million, for fiscal 2019. Sara Castellanos, WSJ, "In a White House Summit on Quantum Technology, Experts Map Next Steps," 31 May 2019 In the past decade alone, quantum... The full text of this article is available to Discover Magazine subscribers only. Linda Marsa, Discover Magazine, "An Atlas of Our Cells," 16 Mar. 2019 This is another one of Samsung’s quantum-dot-using QLED panels, which the company says have a 4ms response time and 178-degree viewing angle. Jeff Dunn, Ars Technica, "Samsung looks to push Thunderbolt 3 with new 34-inch curved monitor," 3 Jan. 2018 The measurement also changes the neutrons quantum wave. Adrian Cho, Science | AAAS, "Quantum measurements could power a tiny, hyper-efficient engine," 10 July 2018 The auto maker is working with IBM ’s commercial partnership program for quantum computing. Sara Castellanos, WSJ, "Mercedes Enlists Quantum Computing to Build a Better Electric Vehicle Battery," 25 Feb. 2019 Clarke is a pioneer in developing sensitive magnetic detectors called superconducting quantum interference devices (SQUIDs). Douglas Messier, Space.com, "Super-Sensitive Device Seeks Axions, Proposed Dark Matter Particles," 2 July 2018 The blueprint recommends that the hubs focus on three areas: developing ultraprecise quantum sensors for biomedicine, navigation, and other applications; hack-proof quantum communication; and quantum computers. Gabriel Popkin, Science | AAAS, "Updated: Quantum physics gets attention—and brighter funding prospects—in Congress," 27 June 2018

Recent Examples on the Web: Adjective

Maldacena’s discovery has enabled physicists to probe black holes and quantum gravity inside the imaginary bottled universe by studying corresponding properties of the gravity-free surface. Quanta Magazine, "Juan Maldacena, Pondering Quantum Gravity by the Pond," 16 June 2019 Daimler joins other automotive companies experimenting with quantum computing’s potential applications. Sara Castellanos, WSJ, "Mercedes Enlists Quantum Computing to Build a Better Electric Vehicle Battery," 25 Feb. 2019 Nothing is definite in Bohr’s quantum world until someone observes it. James Gleick, New York Times, "What Does Quantum Physics Actually Tell Us About the World?," 8 May 2018 To say the quantum world is unintuitive is a staggering understatement. John Timmer, Ars Technica, "Clouds of atoms, vibrating mirrors show their quantum side," 28 Apr. 2018 Her experiments with laser cooling macroscopic objects have laid the groundwork for observing quantum behavior more easily. Jill Kiedaisch, Popular Mechanics, "32 Women Who’ve Changed Life As We Know It," 31 Mar. 2019 Schrödinger’s theorem described the wave function of quantum-mechanical systems. Julia Felsenthal, Vogue, "Searching for Myself in Alice Neel’s Radical Portraits," 26 Feb. 2019 They are only observed via microscopic quantum phenomena, but once this happens, wavefunction interference then becomes apparent. Chris Ciaccia, Fox News, "NASA has created the coldest spot ever," 9 Aug. 2018 Turin speculates that a quantum effect called tunneling might be involved. Tim Folger, Discover Magazine, "How Quantum Mechanics Lets Us See, Smell and Touch," 24 Oct. 2018

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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Statistics for quantum

Last Updated

19 Jun 2019

Look-up Popularity

Time Traveler for quantum

The first known use of quantum was in 1567

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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 quanta (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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Comments on quantum

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


to take the place or position of

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