cap·​sid | \ ˈkap-səd How to pronounce capsid (audio) \

Definition of capsid

: the protein shell of a virus particle surrounding its nucleic acid

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Examples of capsid in a Sentence

Recent Examples on the Web These mega-viruses are hundreds of times larger than most, with capsids that span roughly 400 to 500 nanometers across and full viral forms that can measure up to 750 nanometers across. Maya Wei-haas, National Geographic, "Viruses, explained," 22 Feb. 2019 Cells with the Arc gene crank out proteins that clump into capsids. Lacy Schley, Discover Magazine, "State of Science: Neurons Are Surprising Researchers With Unexpected Abilities," 15 Jan. 2019 Understanding the structure of the capsid could be the key to stopping a viral spread. Jason Daley, Smithsonian, "Herpes Is Kind of Beautiful, On the Molecular Level," 6 Apr. 2018 The finding, along with a huge amount of follow-up work, suggested that these capsid proteins could serve as the basis for a safe and effective vaccine against a virus that causes enormous suffering in the world. Fortune, "Include U Challenge Day 7: Lend Your Privilege," 8 Sep. 2017 With it, researchers were able to show the capsid’s composition from repeating copies of a single four-protein block. Brandon Keim, WIRED, "High-Resolution Imaging Unlocks Viral Secrets," 17 Feb. 2009

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

1959, in the meaning defined above

History and Etymology for capsid

French capside, from Latin capsa case + French -ide -id entry 2

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Statistics for capsid

Time Traveler for capsid

The first known use of capsid was in 1959

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More Definitions for capsid


cap·​sid | \ ˈkap-səd How to pronounce capsid (audio) \

Medical Definition of capsid

: the protein shell of a virus particle that surrounds its nucleic acid

Other Words from capsid

capsidal \ -​səd-​ᵊl How to pronounce capsidal (audio) \ adjective

Comments on capsid

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


meddlesome, informal, or unofficial

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