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

What Causes Chronic Wasting Disease? CWD is caused by infectious proteins called prions. —Jake Parks, Discover Magazine, 5 Nov. 2024

This new medical paradigm impacted not only how external threats were imagined—the hordes of viruses, spores and prions who now appeared to be always threatening to break through our defences—but also how the internal world of the body was envisioned. —Elsa Richardson, TIME, 3 Oct. 2024

Infectious agents known as prions cause chronic wasting disease. —George Petras, USA TODAY, 29 Apr. 2024

However, because the FDA mandates the removal of all tissues shown to carry the prions — such as brains and spinal cords — from poultry diets, the risk is reduced. —Susanne Rust, Los Angeles Times, 18 Apr. 2024

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

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