frequency

noun

fre·​quen·​cy ˈfrē-kwən(t)-sē 

plural frequencies

1

: the fact or condition of occurring frequently

the frequency of automobile accidents

2

a

: the number of times that a periodic function repeats the same sequence of values during a unit variation of the independent variable

b

: the number, proportion, or percentage of items in a particular category in a set of data

3

: the number of repetitions of a periodic process in a unit of time: such as

a

: the number of complete alternations (see alternation sense 1) per second of an alternating current

b

: the number of complete oscillations (see oscillation sense 3) per second of energy (such as sound or electromagnetic radiation) in the form of waves

Synonyms

• prevalence
• frequence

Examples of frequency in a Sentence

the alarming frequency of serious automobile accidents caused by young drivers

The frequency of student errors was frustrating to the young teacher.

Our visits decreased in frequency.

Errors were occurring with increasing frequency.

a sound wave of high frequency

waves having very different frequencies from one another

a current having a frequency of 60 hertz

a radio frequency of 30 megahertz

Recent Examples on the Web

However, it's being seen with increasing frequency in northeastern states along the Atlantic coast, said Madoff, medical director for the Massachusetts Department of Public Health's Bureau of Infectious Disease and Laboratory Sciences. —Phaedra Trethan, USA Today, 3 Sep. 2025

Heat waves are increasing in temperature, frequency and duration, pushing native species like rattlesnakes to their biological limit. —John Leos, AZCentral.com, 3 Sep. 2025

The team then analyzed the EEG signals, looking at how the signals changed over different frequencies, and these were processed through machine-learning models, which could detect when a participant was becoming motion sick in real time with a high degree of accuracy. —New Atlas, 2 Sep. 2025

Courtesy of Centner Wellness She began by healing herself, becoming the patient zero of her own practice, experimenting with hyperbaric oxygen, red-light therapy, frequency beds, supplements, coffee enemas, and more. —Stephan Rabimov, Forbes.com, 2 Sep. 2025

Word History

First Known Use

1600, in the meaning defined at sense 1

Phrases Containing frequency

• extremely high frequency
• extremely low frequency
• frequency distribution
• frequency modulation
• frequency response
• gene frequency
• high frequency
• low frequency
• medium frequency
• radio frequency
• superhigh frequency
• ultrahigh frequency
• very high frequency
• very low frequency

Rhymes for frequency

• infrequency
• multifrequency

Kids Definition

frequency

noun

fre·​quen·​cy ˈfrē-kwən-sē 

plural frequencies

1

: the fact or condition of happening often

2

: how often something happens : rate of repetition

3

: the number of repetitions of a periodic process in a unit of time: as

a

: the number of times per second that an electric current flowing in one direction changes direction then changes back

a current having a frequency of 60 hertz

b

: the number of waves (as of sound or electromagnetic energy) that pass a fixed point each second

a sound having a frequency of 1500 hertz

the frequency of yellow light

4

: the number or proportion of one kind of item in a group

the frequency of chocolate doughnuts in the box

Medical Definition

frequency

noun

fre·​quen·​cy ˈfrē-kwən-sē 

plural frequencies

1

: the number of individuals in a single class when objects are classified according to variations in a set of one or more specified attributes

2

: the number of repetitions of a periodic process in a unit of time