RETARDATION

slowdown, lag, retardation

(noun) the act of slowing down or falling behind

deceleration, slowing, retardation

(noun) a decrease in rate of change; “the deceleration of the arms race”

retardation, mental retardation, backwardness, slowness, subnormality

(noun) lack of normal development of intellectual capacities

retardant, retardent, retardation

(noun) any agent that retards or delays or hinders; “flame-retardant”

retardation

(noun) the extent to which something is delayed or held back

Source: WordNet® 3.1

Etymology

Noun

retardation (countable and uncountable, plural retardations)

The act of retarding or delaying; hindrance.

(acoustics) The distance by which one wave is behind another.

(telegraphy) A decrease in the speed of telegraph signalling.

The extent to which anything is retarded; the result of any retarding or delay; mental, social, or physical slowness.

(colloquial, derogatory, offensive) Extreme stupidity.

That which retards; an obstacle; an obstruction.

(physics) Deceleration; reduction in the magnitude of velocity.

(music) A suspension which resolves upwards.

Source: Wiktionary

Re`tar*da"tion, n. Etym: [L. retardatio: cf. F. retardation.]

1. The act of retarding; hindrance; the act of delaying; as, the retardation of the motion of a ship; -- opposed to Ant: acceleration. The retardations of our fluent motion. De Quinsey.

2. That which retards; an obstacle; an obstruction. Hills, sloughs, and other terrestrial retardations. Sir W. Scott.

3. (Mus.)

Definition: The keeping back of an approaching consonant chord by prolonging one or more tones of a previous chord into the intermediate chord which follows; -- differing from suspension by resolving upwards instead of downwards.

4. The extent to which anything is retarded; the amount of retarding or delay. Retardation of the tide. (a) The lunitidal interval, or the hour angle of the moon at the time of high tide any port; the interval between the transit of the moon and the time of high tide next following. (b) The age of the tide; the retard of the tide. See under Retard, n.

Source: Webster’s Unabridged Dictionary 1913 Edition