n. [ 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 acceleration. [ 1913 Webster ]

The retardations of our fluent motion. De Quinsey. [ 1913 Webster ]

2. That which retards; an obstacle; an obstruction. [ 1913 Webster ]

Hills, sloughs, and other terrestrial retardations. Sir W. Scott. [ 1913 Webster ]

3. (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. [ 1913 Webster ]

4. The extent to which anything is retarded; the amount of retarding or delay. [ 1913 Webster ]

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. [ 1913 Webster ]

n. [ L. tardatio, fr. tardare, tardatum, to retard, delay, fr. tardus slow. ] The act of retarding, or delaying; retardation. [ Obs. ] [ 1913 Webster ]