[ ree-tahr-dey-shuh n ]
/ ˌri tɑrˈdeɪ ʃən /


the act of retarding or state of being retarded.
something that retards; hindrance.
Usually Offensive. slowness or limitation in intellectual understanding and awareness, emotional development, academic progress, etc.See also mental retardation.
Music. a form of suspension that is resolved upward.
Also re·tard·ment [ri-tahrd-muh nt] /rɪˈtɑrd mənt/.

Origin of retardation

1400–50; late Middle English retardacioun < Latin retardātiōn- (stem of retardātiō), equivalent to retardāt(us) (see retard, -ate1) + -iōn- -ion

Related forms

Usage note Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for retardation


less commonly retardment (rɪˈtɑːdmənt)

/ (ˌriːtɑːˈdeɪʃən) /


the act of retarding or the state of being retarded
something that retards; hindrance
the rate of deceleration
psychiatry the slowing down of mental functioning and bodily movement

Derived Forms

retardative or retardatory, adjective
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medicine definitions for retardation


[ rē′tär-dāshən ]


The condition of being relatively slow in mental, emotional, or physical development.
The extent to which something is held back or delayed.
Mental retardation.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.