nucleolus

noun

nu·​cle·​o·​lus nü-ˈklē-ə-ləs How to pronounce nucleolus (audio)
nyü-
plural nucleoli nü-ˈklē-ə-ˌlī How to pronounce nucleolus (audio)
nyü-
: a spherical body of the nucleus of most eukaryotes that becomes enlarged during protein synthesis, is associated with a nucleolus organizer, and contains the DNA templates for ribosomal RNA see cell illustration
nucleolar adjective

Examples of nucleolus in a Sentence

Recent Examples on the Web Still other types of ncRNAs, called small nucleolar RNAs, work within cell compartments called nucleoli to help modify the RNA in ribosomes—a cell’s protein-making factories—as well as transfer RNA and mRNA. Philip Ball, Scientific American, 14 May 2024 In 2019 in Non-Coding RNA, Weber and a co-author weighed the support for phase separation in the cell nucleus and concluded that solid data back its role in forming three structures, including the nucleolus, but not two other structures commonly attributed to the process. Mitch Leslie, Science | AAAS, 21 Jan. 2021 In 2012, Brangwynne and colleagues saw similar fluid features in the nucleolus, a dense mix of proteins, RNA, and DNA that manufactures ribosomes, the cell’s protein factories. Mitch Leslie, Science | AAAS, 21 Jan. 2021 More membraneless structures continued to be found, such as the nucleolus, a dense structure in the cell nucleus. Quanta Magazine, 26 Nov. 2018 But there’s more to the nucleolus than just making ribosomes. Joanna Klein, New York Times, 20 May 2018

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'nucleolus.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

New Latin, from Latin, diminutive of nucleus

First Known Use

1839, in the meaning defined above

Time Traveler
The first known use of nucleolus was in 1839

Dictionary Entries Near nucleolus

Cite this Entry

“Nucleolus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/nucleolus. Accessed 15 Jul. 2024.

Kids Definition

nucleolus

noun
nu·​cle·​o·​lus n(y)ü-ˈklē-ə-ləs How to pronounce nucleolus (audio)
plural nucleoli -ˌlī How to pronounce nucleolus (audio)
: a sphere-shaped body in the cell nucleus that is associated with a particular part of a chromosome, and is rich in ribosomal RNA

Medical Definition

nucleolus

noun
nu·​cle·​o·​lus n(y)ü-ˈklē-ə-ləs How to pronounce nucleolus (audio)
plural nucleoli -ˌlī How to pronounce nucleolus (audio)
: a spherical body of the nucleus of most eukaryotes that becomes enlarged during protein synthesis, is associated with a nucleolus organizer, and contains the DNA templates for ribosomal RNA

called also plasmosome

More from Merriam-Webster on nucleolus

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