frequency

American  

[free-kwuhn-see] / ˈfri kwən si /

noun

• frequencies
  plural

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

Derived Forms

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

Inflected Forms

Nouns

• frequencies
  plural

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

See Examples For:

frequency frequencies

Both sides are now engaged in a constant game of cat and mouse, jumping around the frequency spectrum to jam and avoid each other, and they are increasingly using AI to do that.

From The Wall Street Journal ● Oct. 6, 2026

“Because of their frequency, they can also affect the general public’s right to enjoy the coastline. Therefore, pre-planned setups and professional photography have specific rules and permit requirements.”

From Los Angeles Times ● Oct. 5, 2026

They varied several properties of the setup, including the cavity geometry, characteristic frequency, material thicknesses, dielectric materials, and metallic strips.

From Science Daily ● Oct. 3, 2026

While there isn’t any data to quantify its frequency, as Walsh pointed out, if a phone call does happen, it’s becoming increasingly more common to text before you call.

From Salon ● Sep. 30, 2026

Because they did not burn the land with the same skill and frequency as its previous occupants, the forests grew thicker.

From "1491" by Charles C. Mann

Meanwhile, drones can now be built to use cellphone networks or fiber optic cables to evade the traditional jamming of radio frequencies used by police.

From The Wall Street Journal ● Oct. 8, 2026

Birds in noisy environments consistently produced calls with significantly higher peak frequencies compared with those in quieter habitats, the study said.

From BBC ● Oct. 6, 2026

By scanning through many frequencies and looking for peaks in the response, the researchers could identify the different energy levels.

From Science Daily ● Oct. 1, 2026

Radio frequencies needed for weather forecasts, early warning systems, climate monitoring and water management must be safeguarded against the growing threat of interference from emerging technologies, the United Nations said on Monday.

From Barron's ● Sep. 28, 2026

The pullover cost me four sets of wireless code—the full lot of encoding poems, passwords, and frequencies.

From "Code Name Verity" by Elizabeth Wein

Related Words

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