retardation

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The act or process of retarding.
2. n. The condition of being retarded.
3. n. The extent to which something is held back or delayed.
4. n. Something that retards; a delay or hindrance.
5. n. Mental retardation.
6. n. Music A diminishing of tempo; a retard.

Century Dictionary and Cyclopedia

1. n. The act of retarding or making slower, or its effect; the hindering of motion, growth, or progress, or the hindrance effected; the act of delaying or impeding.
2. n. In physics:
3. n. A continuous decrement of velocity; a negative acceleration.
4. n. In acoustics and optics, the distance by which one wave is behind another. Better called retard, being translation of French retard.
5. n. Postponement; deferment.
6. n. Specifically, in music:
7. n. The act, process, or result of diminishing the speed or pace of the tempo
8. n. The prolongation of a concordant tone into a chord where it is a discord which is resolved upward: opposed to anticipation, and distinguished from suspension by the upward resolution
9. n. In telegraphy, decrease in the speed of telegraph-signaling due to self-induction and induction from surrounding conductors.
10. n. That which retards; a hindrance; an obstruction; an impediment.

Wiktionary

1. n. The act of retarding or delaying; hindrance.
2. n. The extent to which anything is retarded; the result of any retarding or delay; mental, social, or physical slowness.
3. n. That which retards; an obstacle; an obstruction.
4. n. physics Deceleration; reduction in the magnitude of velocity.
5. n. music A suspension which resolves upwards.

GNU Webster's 1913

1. n. The act of retarding; hindrance; the act of delaying; ; -- opposed to acceleration.
2. n. That which retards; an obstacle; an obstruction.
3. n. (Mus.) 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. n. The extent to which anything is retarded; the amount of retarding or delay.

WordNet 3.0

1. n. a decrease in rate of change
2. n. the extent to which something is delayed or held back
3. n. any agent that retards or delays or hinders
4. n. lack of normal development of intellectual capacities
5. n. the act of slowing down or falling behind