1. A situation in which the apparent solution of one problem in a chain of circumstances creates a new problem and increases the difficulty of solving the original problem. Also called vicious cycle.
2. A condition in which a disorder or disease gives rise to another that subsequently affects the first.
3. Logic. A fallacy in reasoning in which the premise is used to prove the conclusion, and the conclusion used to prove the premise.

[Translation of New Latin circulus vitiōsus, circular argument : Medieval Latin circulus, circular argument + Latin vitiōsus, flawed, faulty.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.