retardation

[ree-tahr-dey-shuh n] /ˌri tɑrˈdeɪ ʃən/
noun
1.
the act of retarding or state of being retarded.
2.
something that retards; hindrance.
3.
Usually Offensive. slowness or limitation in intellectual understanding and awareness, emotional development, academic progress, etc.
See also mental retardation.
4.
Music. a form of suspension that is resolved upward.
Also, retardment
[ri-tahrd-muh nt] /rɪˈtɑrd mənt/ (Show IPA).
Origin
1400-50; late Middle English retardacioun < Latin retardātiōn- (stem of retardātiō), equivalent to retardāt(us) (see retard, -ate1) + -iōn- -ion
Related forms
retardative
[ri-tahr-duh-tiv] /rɪˈtɑr də tɪv/ (Show IPA), retardatory
[ri-tahr-duh-tawr-ee, -tohr-ee] /rɪˈtɑr dəˌtɔr i, -ˌtoʊr i/ (Show IPA), adjective
nonretardation, noun
nonretardative, adjective
nonretardatory, adjective
nonretardment, noun
Usage note
See retarded.
British Dictionary definitions for retardation

retardation

/ˌriːtɑːˈdeɪʃən/
noun
1.
the act of retarding or the state of being retarded
2.
something that retards; hindrance
3.
the rate of deceleration
4.
(psychiatry) the slowing down of mental functioning and bodily movement
Derived Forms
retardative, retardatory, adjective
Word Origin and History for retardation
n.

early 15c., "fact or action of making slower in movement or time," from Latin retardationem (nominative retardatio) "a delaying," noun of action from past participle stem of retardare "to make slow, delay, keep back, hinder," from re- (see re-), + tardare "to slow" (see tardy). Sense of "educational slowness" is from 1907.

retardation in Medicine

retardation re·tar·da·tion (rē'tär-dā'shən)
n.

  1. The condition of being relatively slow in mental, emotional, or physical development.

  2. The extent to which something is held back or delayed.

  3. Mental retardation.