Real Dictionary

prion in American English
any of a group of tiny infectious agents composed mainly or entirely of protein: though lacking in demonstrable nucleic acid, prions are capable of self-replication and are thought to be the cause of various degenerative diseases of the nervous systems of

prion in American English 1
noun: any of several petrels of the genus Pachyptila, located in the oceans of the Southern Hemisphere and having serrated edges on the bill

prion in American English 2
noun: a tiny proteinaceous particle, likened to viruses and viroids, but having no genetic component, thought to be an infectious agent in bovine spongiform encephalopathy, Creutzfeldt-Jakob disease, and similar encephalopathies

prion in British English 1
noun: any of various dovelike petrels of the genus Pachyptila of the southern oceans that have a serrated bill

prion in British English 2
noun: a protein in the brain, an abnormal form of which is thought to be the transmissible agent responsible for certain spongiform encephalopathies, such as BSE, scrapie, Creutzfeldt-Jakob disease, and kuru