mol·​e·​cule | \ ˈmä-li-ˌkyül How to pronounce molecule (audio) \

Definition of molecule

1 : the smallest particle of a substance that retains all the properties (see property sense 1a) of the substance and is composed of one or more atoms (see atom sense 1a) a molecule of water a molecule of oxygen
2 : a tiny bit : particle a molecule of political honestyTime

Keep scrolling for more

Examples of molecule in a Sentence

There is not a molecule of evidence to support these charges. not a molecule of sense in that girl
Recent Examples on the Web This tissue is filled with neurons, which pick up the odor molecule and transport it through the olfactory bulb and into the brain, where it's interpreted as, say, the scent of roses. Erika Edwards, NBC News, "Loss of smell and taste can linger after Covid or come back different," 6 Jan. 2021 Some viruses have genetic codes of DNA, the same molecule that carries the genetic information in human cells. Sarah Toy, WSJ, "New Covid-19 Strains: What Scientists Know About Coronavirus Variants," 1 Jan. 2021 The lab doesn’t sequence the entire DNA molecule, much of which is repetitious and uninformative, but maps about a million key locations. Douglas Preston, The New Yorker, "The Skeletons at the Lake," 7 Dec. 2020 TGen has already started studying the molecule in collaboration with professor Maurizio Zanetti's lab at the University of California, San Diego. Amanda Morris, The Arizona Republic, "Arizona researchers discover potential new genetic target against COVID-19 infections," 6 Dec. 2020 It’s the molecule that actually instructs your cells what to make, such as proteins. Sy Mukherjee, Fortune, "The science behind the leading COVID vaccines will lead to faster manufacturing," 5 Dec. 2020 The final clue was buried in an industry report from 1983, which contained the exact formula of 6PPD-quinone, the molecule created when 6PPD reacts with ozone. Erik Stokstad, Science | AAAS, "Common tire chemical implicated in mysterious deaths of at-risk salmon," 3 Dec. 2020 An understanding of that structure could define BCL-XL’s binding properties, which is the first step in inhibiting the molecule. Scientific American, "An Ongoing Revolution in Blood Cancer," 1 Dec. 2020 The sigma-1 receptor—the ER molecule targeted by fluvoxamine and other SSRIs—also emerged as a promising target in an independent analysis designed to fight the pandemic with repurposed drugs. Esther Landhuis, Wired, "How a Medication for OCD Ended Up in a Covid-19 Trial," 19 Nov. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'molecule.' 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 molecule

1701, in the meaning defined at sense 1

History and Etymology for molecule

French molécule, from New Latin molecula, diminutive of Latin moles mass

Keep scrolling for more

Learn More about molecule

Time Traveler for molecule

Time Traveler

The first known use of molecule was in 1701

See more words from the same year

Statistics for molecule

Last Updated

15 Jan 2021

Cite this Entry

“Molecule.” Dictionary, Merriam-Webster, Accessed 18 Jan. 2021.

Keep scrolling for more

More Definitions for molecule


How to pronounce molecule (audio)

English Language Learners Definition of molecule

: the smallest possible amount of a particular substance that has all the characteristics of that substance
: a very small amount of something


mol·​e·​cule | \ ˈmä-li-ˌkyül How to pronounce molecule (audio) \

Kids Definition of molecule

: the smallest portion of a substance having the properties of the substance a molecule of water


mol·​e·​cule | \ ˈmäl-i-ˌkyü(ə)l How to pronounce molecule (audio) \

Medical Definition of molecule

: the smallest particle of a substance that retains all the properties of the substance and is composed of one or more atoms

Keep scrolling for more

Comments on molecule

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


Test Your Vocabulary

Words of Snow and Ice Quiz

  • image1037863653
  • Which of the following refers to thin, bending ice, or to the act of running over such ice?
True or False

Test your knowledge - and maybe learn something along the way.


Anagram puzzles meet word search.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!