nucleus

noun
nu·​cle·​us | \ ˈnü-klē-əs How to pronounce nucleus (audio) , ˈnyü- \
plural nuclei\ ˈnü-​klē-​ˌī How to pronounce nucleus (audio) , ˈnyü-​ \ also nucleuses

Definition of nucleus

1a : the small bright body in the head of a comet
b : the small brighter and denser portion of a galaxy (see galaxy sense 1b)
2 : a central point, group, or mass about which gathering, concentration, or accretion takes place: such as
a : a cellular organelle of eukaryotes that is essential to cell functions (such as reproduction and protein synthesis), is composed of nucleoplasm and a nucleoprotein-rich network from which chromosomes and nucleoli arise, and is enclosed in a definite membrane — see cell illustration
b : a mass of gray matter or group of cell bodies of neurons in the central nervous system
c : a characteristic and stable complex of atoms or groups in a molecule (see molecule sense 1) especially : ring the naphthalene nucleus
d : the positively charged central portion of an atom that comprises nearly all of the atomic mass and that consists of protons and usually neutrons
3 : the peak of sonority in the utterance of a syllable
4 : a basic or essential part : core players who are the nucleus of the team

Examples of nucleus in a Sentence

a college campus that was a nucleus of opposition to the war the nucleus of the movement's methodology has always been passive resistance
Recent Examples on the Web Clearly, the cuneate nucleus is a far more interesting brain region than it has been given credit for. Sliman Bensmaia, Scientific American, 16 May 2022 The nucleus of it was — and continues to be — the Kahi Wrinkle Bounce Multi Balm. Devon Abelman, Allure, 26 Apr. 2022 The nucleus of that is to understand oneself, authentically. Expert Panel®, Forbes, 22 Apr. 2022 More research is needed to understand why the nucleus is so dark. Denise Chow, NBC News, 14 Apr. 2022 That creepy gathering, which Edelman skewers to perfection, forms the nucleus of his show. Alexandra Schwartz, The New Yorker, 28 Mar. 2022 Limon, about 90 miles southeast of Denver, forms the nucleus of the sprawling project. NBC News, 12 Mar. 2022 Cook, the nucleus of the power-pop band, along with most of his live touring outfit and co-writers and producers, did what pretty much every other band did in the spring of 2020 – called off the tour. Brendan Menapace, SPIN, 8 Mar. 2022 Ukraine’s largest plaza, and the nucleus of public life in the city — was seen by many Ukrainians as brazen evidence that the Russian invasion wasn’t just about hitting military targets but also about breaking their spirit. chicagotribune.com, 2 Mar. 2022 See More

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

First Known Use of nucleus

1668, in the meaning defined at sense 1a

History and Etymology for nucleus

New Latin, from Latin, kernel, from nuc-, nux nut — more at nut

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Time Traveler for nucleus

Time Traveler

The first known use of nucleus was in 1668

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Dictionary Entries Near nucleus

nucleotide

nucleus

nucleus of Pander

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Statistics for nucleus

Last Updated

18 May 2022

Cite this Entry

“Nucleus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/nucleus. Accessed 27 May. 2022.

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More Definitions for nucleus

nucleus

noun
nu·​cle·​us | \ ˈnü-klē-əs How to pronounce nucleus (audio) , ˈnyü- \
plural nuclei\ -​klē-​ˌī \

Kids Definition of nucleus

1 : a usually round part of most cells that is enclosed in a double membrane, controls the activities of the cell, and contains the chromosomes
2 : the central part of an atom that comprises nearly all of the atomic mass and that consists of protons and neutrons
3 : a central point, group, or mass Those players are the nucleus of the team.

nucleus

noun
nu·​cle·​us | \ ˈn(y)ü-klē-əs How to pronounce nucleus (audio) \
plural nuclei\ -​klē-​ˌī How to pronounce nucleus (audio) \ also nucleuses

Medical Definition of nucleus

1 : a cellular organelle of eukaryotes that is essential to cell functions (as reproduction and protein synthesis), is composed of nuclear sap and a nucleoprotein-rich network from which chromosomes and nucleoli arise, and is enclosed in a definite membrane
2 : a mass of gray matter or group of nerve cells in the central nervous system
3 : a characteristic and stable complex of atoms or groups in a molecule especially : ring sense 2 the naphthalene nucleus
4 : the positively charged central portion of an atom that comprises nearly all of the atomic mass and that consists of protons and neutrons except in hydrogen which consists of one proton only

More from Merriam-Webster on nucleus

Nglish: Translation of nucleus for Spanish Speakers

Britannica English: Translation of nucleus for Arabic Speakers

Britannica.com: Encyclopedia article about nucleus

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