prion

1 of 2

noun (1)

pri·​on ˈprī-ˌän 

: 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 

: 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

Wolves, however, are immune to the prions, deactivating them through digestion. —Ted Williams, Denver Post, 26 Mar. 2025

Misfolded proteins called prions damage a victim’s brain cells, cause symptoms such as memory loss and confusion, and inevitably kill them. —Christie Wilcox, science.org, 27 Dec. 2024

The wave of prions slowly accumulates, spreading through the spleen and the lymph nodes and through the peripheral nervous system into the central nervous system. —Sophie Hartley, Scientific American, 10 Jan. 2025

But in other cells, especially some neurons in the brain, a misfolded prion is a death sentence. —Sophie Hartley, Scientific American, 10 Jan. 2025

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

Phrases Containing prion

• prion disease
• prion protein

Rhymes for prion

• anton
• argon
• axon
• baronne
• baryon
• baton
• boron
• buisson
• bygone
• capon
• cardon
• chiffon

Medical Definition

prion

noun

pri·​on ˈprē-ˌän 

: 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