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)

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 Elena Polozova, 25, a former quantum computing researcher who studied at MIT, was the research czar. Annie Vainshtein, SFChronicle.com, "How does an SF house with 11 roommates navigate the coronavirus? It’s complicated," 18 Sep. 2020 Her approach was to focus on a compound’s quantum characteristics, which arise from its subatomic particles and the counterintuitive laws of quantum mechanics. Sarah Scoles, Wired, "‘Dr. Phosphine’ and the Possibility of Life on Venus," 14 Sep. 2020 In 1994, mathematician Peter Shor invented an algorithm, that if run on a sufficiently powerful quantum computer, would easily find these two primes. Jeremy Kahn, Fortune, "Quantum computers threaten to end digital security. Here’s what’s being done about it," 11 Sep. 2020 Get a taste of Samsung’s quantum technology by sizing down. Brittany Vincent, CNN Underscored, "Shop the best Labor Day TV sales going on right now," 5 Sep. 2020 But Google’s work makes Aspuru-Guzik optimistic that quantum computing can solve interesting problems in the not too distant future. Neil Savage, Scientific American, "Google’s Quantum Computer Achieves Chemistry Milestone," 4 Sep. 2020 At the other end of the hype cycle, four-year-old Toronto startup Xanadu says its cloud quantum computing platform is open for business. Adam Lashinsky, Fortune, "Why AT&T is leaving the lucrative ad-tech business," 3 Sep. 2020 An innovative protective noise field extends a qubit's quantum state to 22 milliseconds. Caroline Delbert, Popular Mechanics, "Scientists Extend Quantum States by 22 Milliseconds. That's an Eternity.," 21 Aug. 2020 The quantum-computing companies that AWS customers can experiment with have different technological approaches. Sara Castellanos, WSJ, "Amazon’s Cloud Unit to Offer Quantum Computing From 3 Tech Companies," 13 Aug. 2020 Recent Examples on the Web: Adjective That’s exactly what will be required to start to make a full-fledged quantum computer with thousands of logical qubits. Adrian Cho, Science | AAAS, "IBM promises 1000-qubit quantum computer—a milestone—by 2023," 15 Sep. 2020 Companies like JPMorgan Chase and ExxonMobil are already signed on as customers of IBM’s quantum hardware. Robert Hackett, Fortune, "IBM plans a huge leap in superfast quantum computing by 2030," 15 Sep. 2020 And four years later, Gambetta and his colleagues became the first in the world to make quantum computers available globally and for free through the cloud—to anyone. Dario Gil, Scientific American, "How to Ensure the U.S.’s Quantum Future," 20 Aug. 2020 That suggests gravity is not, in fact, shaking particles out of their quantum superpositions. George Musser, Science | AAAS, "One of quantum physics’ greatest paradoxes may have lost its leading explanation," 7 Sep. 2020 Sarachik also led experiments that explored the quantum behavior of molecules that act like magnets. Kenneth Chang, Star Tribune, "'I'm not a quitter': Myriam Sarachik never gave up on physics," 3 Sep. 2020 In 1978, German biophysicist Klaus Schulten suggested a third possibility after studying a class of obscure chemical reactions influenced by quantum effects. Jo Marchant, Wired, "The Oysters That Knew What Time It Was," 1 Sep. 2020 In February, the White House outlined a plan for annual spending on AI to rise to more than $2 billion between 2020 and 2022, and funding for quantum information science to increase to $860 million between that time frame. Sara Castellanos, WSJ, "White House Plans to Boost AI, Quantum Funding by 30%," 14 Aug. 2020 This is where the Endgame version of events comes into play, and where the quantum experiment begins. Caroline Delbert, Popular Mechanics, "Quantum Mechanics Proves 'Back to the Future' Is B.S.," 30 July 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

22 Sep 2020

Cite this Entry

“Quantum.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/quantum. Accessed 23 Sep. 2020.

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More Definitions for quantum


How to pronounce quantum (audio)

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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