1) Amentia 2) Backwardness 3) Deceleration 4) Hindrance 5) Idiocy 6) Imbecility 7) Lag 8) Mongolianism 9) Mongolism 10) Moronity 11) Retardant 12) Retardent 13) Slowdown 14) Slowing 1) Deceleration 2) Fastness 3) Slowing 4) Slowness in progress 5) Speed 6) Swiftness 
• (n.) The act of retarding; hindrance; the act of delaying; as, the retardation of the motion of a ship; -- opposed to acceleration. • (n.) The extent to which anything is retarded; the amount of retarding or delay. • (n.) The keeping back of an approaching consonant chord by prolonging one or more tones of a previous chord into the...
(L. retardare to slow down, impede) delay; hindrance; delayed development.
This is the time difference between Moon rise one day, and Moon rise the following day.
Delay, hindrance, delayed development. ... Origin: L. Retardare = to slow down, impede ... (18 Nov 1997) ... 
(re″tahr-da´shәn) delay; hindrance; delayed development. fetal growth retardation , intrauterine growth retardationIUGR birth weight below the tenth percentile for gestational age for infants in a given population; classified as symmetric or proportionate (bot...The delaying of the initial setting time of concrete to allow more time to work.
Re`tar·da'tion noun [ Latin retardatio : confer French retardation .] 1. The act of retarding; hindrance; the act of delaying; as, the retardation of the motion of a ship; -- opposed to acceleration . « The retardations of our fluent motion.» 
Backwardness.
Type: Term Pronunciation: rē-tahr-dā′shŭn Definitions: 1. The slowing or limitation of development.
In music retardation is the keeping back of an approaching consonant chord by prolonging one or more tones of a previous chord into the intermediate chord which follows. It differs from suspension by resolving upwards instead of downwards.
[n] - the extent to which something is delayed or held back 2. [n] - lack of normal development of intellectual capacities
The amount of time by which corresponding tidal phases grow later day by day (about 50 minutes).
mental retardation noun lack of normal development of intellectual capacities