retardation

retardation:

see mental retardation.

retardation

(ree-tar-day -shŏn) The difference in the Moon's rising time between successive nights.

Retardation

 

in biology, the late formation and delayed development of an organ in offspring as compared with ancestors. Retardation depends on the beginning of the functioning of an organ and consequently on the environmental conditions in which the development of the individual organism (ontogeny) occurs.

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Retardation

 

(1) In linguistics, a variation of the phenomenon of phonetic analogy consisting of a change in the form of a word (lexeme) under the influence of the phonetic form of another lexeme that precedes it in context. Retardation is characteristic of numbers, for example, Tadzhik shonzdakh (“sixteen”), instead of the expected shazdakh, by analogy with ponzdakh (“fifteen”). The same phenomenon operating in the reverse direction is known as anticipation, for example, Russian deviat’ (“nine”), instead of neviat’, under the influence of desiat’ (“ten”).

(2) In poetics, a compositional technique of holding back the development of the plot; it is accomplished by such means as lyric digressions, descriptions of landscapes or interiors, and the repetition of episodes of the same type.

retardation

[‚rē‚tär′dā·shən]

(medicine)

Slow mental or physical functioning.

(navigation)

The amount of delay in time or phase angle introduced by the resistivity of the surface over which the radio wave in radio navigation is passing.

(oceanography)

The amount of time by which corresponding tidal phases grow later day by day, averaging approximately 50 minutes.

(optics)

In interference microscopy, the difference in optical path between the light passing through the specimen and the light bypassing the specimen. Also known as optical-path difference.

retardation

Reduction in the rate of hardening or setting; an increase in the time required to reach initial and final set or to develop early strength of fresh concrete, mortar, plaster, or grout.