frequency

American  

[free-kwuhn-see] / ˈfri kwən si /

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.

   Synonyms:

   recurrence, repetition, regularity

2. rate of occurrence.

   The doctor has increased the frequency of his visits.

3. Physics.

   1. the number of periods or regularly occurring events of any given kind in unit of time, usually in one second.

   2. the number of cycles or completed alternations per unit time of a wave or oscillation. F; 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.

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frequency British  

/ ˈfriːkwənsɪ /

noun

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.  ν.   f.  physics 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

   1. the number of individuals in a class ( absolute frequency )

   2. the ratio of this number to the total number of individuals under survey ( relative frequency )

5. ecology

   1. the number of individuals of a species within a given area

   2. the percentage of quadrats that contains individuals of a species

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frequency Scientific  

/ frē′kwən-sē /

1. Physics The rate at which a repeating event occurs, such as the full cycle of a wave. Frequencies are usually measured in hertz.

2. Physics Compare amplitude See also period

3. Mathematics The ratio of the number of occurrences of some event to the number of opportunities for its occurrence.

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frequency Cultural  

1. 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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Other Word Forms

• nonfrequence noun
• nonfrequency noun
• overfrequency noun
• underfrequency noun

Etymology

Origin of frequency

First recorded in 1545–55, frequency is from the Latin word frequentia assembly, multitude, crowd. See frequent, -cy

Explanation

Frequency measures how often things repeat over time. City buses often reach stops at a frequency of every 15 minutes, unless it's snowing or raining really hard. In that case, the frequency will slow. You probably know the word frequent, a synonym for often. So, it is tempting to think frequency describes something that happens often. However, this isn't true: frequency describes any rate of time at which something repeats. For example, from Earth, Halley's Comet is visible at a frequency of 76 years — it's not frequent, but it is on schedule.

Example Sentences

Just as two radio stations in the same city can’t broadcast on the same frequency, companies such as AT&T, Verizon, and SpaceX need spectrum for their customers’ calls and data.

From Barron's • Apr. 15, 2026

When taken at the appropriate dose, these drugs help dissolve crystal deposits and reduce the frequency of painful gout attacks.

From Science Daily • Apr. 14, 2026

Despite improvements, AI models still vary in hallucination frequency, leading to misinformation and user “cognitive surrender.”

From The Wall Street Journal • Apr. 14, 2026

The state’s rainfall at the end of the year will be determined by more factors, such as the frequency and strength of atmospheric rivers, than whether it’s technically an El Niño year, he said.

From Los Angeles Times • Apr. 9, 2026

Perhaps at an adjacent frequency or a faster timing, there would be another message, which would turn out to be a primer, an introduction to the language of interstellar discourse.

From "Cosmos" by Carl Sagan

Related Words

• density
• number
• prevalence
• recurrence
• regularity
• repetition