quan·​tum | / ˈkwän-təm How /

plural quanta/ ˈkwän-​tə How /

Definition of quantum

 (Entry 1 of 2)

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)

2 : of, relating to, or employing the principles of quantum mechanics quantum physics

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 In the lab, Schöllhorn’s team calculated each nest’s quantum yield, or its capacity to emit light when fed a certain number of photons. Katherine J. Wu, The Atlantic, 24 Aug. 2021 Put another way, observing a quantum system fundamentally changes the system. Courtney Linder, Popular Mechanics, 23 Aug. 2021 After all, there’s no such job as a quantum mechanic. Rhett Allain, Wired, 20 Aug. 2021 Tensors are nothing new to physicists, who have long used them to describe, for example, the different possible quantum states of a particle, but network theorists adopted this tool to expand on the power of matrices in high-dimensional data sets. Quanta Magazine, 19 Aug. 2021 Those ripples may have originated in the universe’s earliest moments, when instead of space and time there was a kind of primordial quantum foam. Dan Falk, Smithsonian Magazine, 26 July 2021 Nobody could’ve predicted that developing more and more complex, tortuous ways of stretching credit to cover new state expenses would eventually result in the quantum leaps of European empires in the centuries to come. Washington Post, 21 July 2021 Has percolation been applied to advancing LQG and quantum gravity? Scientific American, 19 July 2021 Either of these could easily suck me in with the gravity of a spicy-roasted mocha-chocolate quantum singularity. Amy Drew Thompson, orlandosentinel.com, 16 July 2021 Recent Examples on the Web: Adjective Scientists from around the world claim to have harnessed a time crystal inside a quantum computer. Caroline Delbert, Popular Mechanics, 4 Aug. 2021 The new time crystal demo marks one of the first times a quantum computer has found gainful employment. Quanta Magazine, 2 Aug. 2021 The startup, co-founded by Shahar Keinan and Bill Shipman, came out of stealth a year ago, revealing the first-ever drug discovery platform using a quantum computer, cost-efficiently scanning billions of molecules from a large chemical space. Gil Press, Forbes, 25 June 2021 And even with compression, longer baselines would still warrant quantum repeaters. Anil Ananthaswamy, Scientific American, 19 Apr. 2021 Time crystals might introduce a better method for sustaining quantum computing, according to Yao, who published a blueprint for making time crystals in 2017. Washington Post, 12 Aug. 2021 Wigner crystal melting is a quantum phase transition — one that is similar to an ice cube becoming water, but without any heating involved. Quanta Magazine, 12 Aug. 2021 Merkel studied physics at Leipzig University and earned a doctorate in quantum chemistry in Berlin. Margaret Talbot, The New Yorker, 11 Aug. 2021 And that instability makes using a quantum computer problematic. Chris Smith, BGR, 1 Aug. 2021

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.

See More

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

Learn More About quantum

Statistics for quantum

Cite this Entry

“Quantum.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/quantum. Accessed 1 Sep. 2021.

Seen & Heard

People are talking about

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)

quan·​tum | / ˈkwänt-əm How /

plural quanta/ ˈkwänt-​ə How /

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

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).

Write us

Find us at the office

Blotner- Kwas street no. 55, 39246 Canberra, Australia

Give us a ring

Dymon Rothfuss
+78 715 483 676
Mon - Fri, 10:00-22:00

Write us