Definition of "differentia" [dif•fer•en•ti•a]

• An attribute that distinguishes one entity from another, especially an attribute that distinguishes one species from others of the same genus. (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.

• "The character that distinguishes one species from others within the same genus is called the differentia specifica."
• "For we are still faced with the apparent fact that genus + differentia constitutes a plurality even if the differentia is the last, or “completing,” one."
• "Popularly this was described by saying that the differentia is the knife that carves a species out of the genus."