prion | meaning of prion in Longman Dictionary of Contemporary English | LDOCE

From Longman Dictionary of Contemporary Englishprionpri‧on /ˈpraɪɒn, ˈpriː- $ -ɑːn/ noun [countable]    a very small piece of protein that is thought to cause some brain diseases such as BSEExamples from the Corpusprion• There are three human prion diseases and four main prion diseases of animals.• Computer models are used to create three-dimensional models of prions, helping scientists understand the structural transformation they undergo to turn deadly.• A normal gene produces a normal protein, then something goes wrong and the body starts turning out prions.• No one has been able to create purified prions in a system that would rule out the presence of viruses.• Both patients described were heterozygous for the missense mutation at codon 200 of the prion protein gene.• Healthy proteins, which have not met up with prions, reside quietly in the membranes of nerve cells in the brain.Origin prion (1900-2000) proteinaceous “containing protein” ((19-21 centuries)) + infectious particle