prion
noun (1)
pri·on
| \ ˈprī-ˌän
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Definition of prion
(Entry 1 of 2)
: any of several small petrels (genus Pachyptila of the family Procellariidae) of the southern hemisphere that are bluish gray above and white below
prion
noun (2)
pri·on
| \ ˈprē-ˌän
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Definition of prion (Entry 2 of 2)
: 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