Definition of "retrorse" []

• Directed or turned backward or downward. (adjective)

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 fish you really have to watch out for is the candirú, a toothpick-shaped catfish that wriggles into bodily orifices, throws out retrorse spines, and can be removed only through surgery."