prion

1 of 2

noun (1)

pri·​on ˈprī-ˌän How to pronounce prion (audio)
: any of several small petrels (genus Pachyptila of the family Procellariidae) of the southern hemisphere that are bluish gray above and white below

prion

2 of 2

noun (2)

pri·​on ˈprē-ˌän How to pronounce prion (audio)
: prion protein
A prion is a protein of unknown function that resides on the surface of brain cells.Sidney Perkowitz
especially : an abnormal form of prion protein that in mammals includes pathogenic forms which arise sporadically, as a result of genetic mutation, or by transmission (as by ingestion of infected tissue) and which upon accumulation in the brain cause a prion disease (such as bovine spongiform encephalopathy or Creutzfeldt-Jakob disease)
Abnormal proteins, known as prions, may trigger mad-cow disease simply by coming into contact with healthy proteins in the brain. Time
… the infectious prion conformation replicates itself in a host by catching the 'benign' host prion protein and forcing it into the infectious conformation. Roland Riek

Examples of prion in a Sentence

Recent Examples on the Web
Noun
Misfolded proteins called prions essentially burn holes in the deer’s brain and cause severe physical decline before killing the deer slowly. Katie Hill, Outdoor Life, 29 Feb. 2024 Classic prion diseases occur when PrP prions cascade, infecting other prions and causing them to malfunction. Erin Prater, Fortune Well, 1 Feb. 2024 Those prions can then infect living deer that interact with them through grazing or otherwise. Katie Hill, Outdoor Life, 21 Dec. 2023 The prions accumulate into toxic clumps that damage the brain and eventually lead to death. Erin Prater, Fortune Well, 1 Feb. 2024 Although Alzheimer’s is not a prion disease, some separate research suggests that the two proteins that are hallmarks in Alzheimer’s disease — amyloid beta and tau — behave like prions. Jacqueline Howard, CNN, 29 Jan. 2024 Chronic wasting disease is caused by infectious proteins called prions. Erin Prater, Fortune Well, 26 Jan. 2024 Animals can also become infected if their feed or pasture is contaminated with the prions carrying it. Li Cohen, CBS News, 17 Nov. 2023 Scientists believe that chronic wasting disease is caused by misfolded proteins called prions. Margaret Osborne, Smithsonian Magazine, 30 Nov. 2023

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'prion.' 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

Noun (1)

New Latin, from Greek priōn saw, from priein to saw; from its sawlike bill

Noun (2)

proteinaceous + infectious + -on entry 2

First Known Use

Noun (1)

1848, in the meaning defined above

Noun (2)

1982, in the meaning defined above

Time Traveler
The first known use of prion was in 1848

Dictionary Entries Near prion

Cite this Entry

“Prion.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/prion. Accessed 21 Apr. 2024.

Medical Definition

prion

noun
pri·​on ˈprē-ˌän How to pronounce prion (audio)
: any of various infectious proteins that are abnormal forms of normal cellular proteins, that proliferate by inducing the normal protein to convert to the abnormal form, and that in mammals include pathogenic forms which arise sporadically, as a result of genetic mutation, or by transmission (as by ingestion of infected tissue) and which upon accumulation in the brain cause a prion disease

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