frequencies

frequency

[free-kwuhn-see]
noun, plural frequencies.
1.
Also, frequence. the state or fact of being frequent; frequent occurrence: We are alarmed by the frequency of fires in the neighborhood.
2.
rate of occurrence: The doctor has increased the frequency of his visits.
3.
Physics.
a.
the number of periods or regularly occurring events of any given kind in unit of time, usually in one second.
b.
the number of cycles or completed alternations per unit time of a wave or oscillation. Symbol: F; Abbreviation: freq.
4.
Mathematics. the number of times a value recurs in a unit change of the independent variable of a given function.
5.
Statistics. the number of items occurring in a given category.

Origin:
1545–55; < Latin frequentia assembly, multitude, crowd. See frequent, -cy

nonfrequence, noun
nonfrequency, noun
overfrequency, noun
underfrequency, noun, plural underfrequencies.

1. regularity, repetition, recurrence.
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World English Dictionary
 frequency (ˈfriːkwənsɪ) —n , pl -cies 1. the state of being frequent; frequent occurrence 2. the number of times that an event occurs within a given period; rate of recurrence 3. physics ν, f the number of times that a periodic function or vibration repeats itself in a specified time, often 1 second. It is usually measured in hertz 4. statistics a.  the number of individuals in a class (absolute frequency) b.  the ratio of this number to the total number of individuals under survey (relative frequency) 5. ecology a.  the number of individuals of a species within a given area b.  the percentage of quadrats that contains individuals of a species [C16: from Latin frequentia a large gathering, from frequēns numerous, crowded]

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Etymonline
Word Origin & History

frequency
1640s, "fact of occurring often," from L. frequentia (see frequent). Earlier it had been used in a now-bsolete sense of "state of being crowded" (mid-16c.); sense in physics, "rate of recurrence," especially of a vibration, is from 1831. In radio electronics, frequency
modulation (1922, abbreviated F.M.) as a system of broadcasting is distinguished from amplitude modulation (or A.M.).
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Science Dictionary
 frequency   (frē'kwən-sē)  Pronunciation Key  Physics The rate at which a repeating event occurs, such as the full cycle of a wave. Frequencies are usually measured in hertz. Compare amplitude. See also period. Mathematics The ratio of the number of occurrences of some event to the number of opportunities for its occurrence.
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American Heritage
Cultural Dictionary

frequency definition

In physics, the number of crests of a wave that move past a given point in a given unit of time. The most common unit of frequency is the hertz (Hz), corresponding to one crest per second. The frequency of a wave can be calculated by dividing the speed of the wave by the wavelength. Thus, in the electromagnetic spectrum, the wavelengths decrease as the frequencies increase, and vice versa.

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