Definition of "prion" [pri•on]

• A microscopic protein particle similar to a virus but lacking nucleic acid, thought to be the infectious agent responsible for scrapie and certain other degenerative diseases of the nervous system. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "You say she disputed the name prion because it did not behave as a protein under radiation."
• "The infectious agent is commonly called a prion, the pr-i standing for proteinaceous infectious, though my mother, in fact, always disputed the term because her work showed that the agent was not destroyed by radiation that would inactivate both DNA and protein. reply"
• "Fri, 01/29/2010 - 05: 34 — Naomie (not verified) the name prion"