What does frequency mean?
Frequency is the rate at which something occurs or repeats within a given period of time. In ordinary use it answers the question 'how often?': one might discuss the frequency of train services, the frequency of a patient's headaches, or the frequency with which a word appears in a text. In physics and engineering the term acquires a precise meaning — the number of complete cycles of a wave or oscillation per second, measured in hertz — making it fundamental to radio, sound, light, and alternating current. Statistics uses the word too, for the count of times a particular value occurs in a set of data. Neutral and versatile, frequency belongs equally to casual conversation and technical writing, and its derivatives 'frequent' and 'frequently' are among the most commonly used adjectives and adverbs in English. Derived from the Latin 'frequentia', meaning a crowded assembly, the word has traveled from describing packed gatherings to measuring everything from heartbeats to radio waves.
nounThe rate at which something occurs or is repeated over a particular period of time; in physics, the number of complete cycles of a wave or oscillation per second, measured in hertz.
- The rate at which something happens or recurs over a given period (e.g. 'the frequency of accidents').
- Physics: the number of complete cycles of a wave, oscillation, or periodic phenomenon per unit time, measured in hertz.
- Statistics: the number of times a value appears in a dataset.
"The frequency of bus services drops sharply after midnight."
"She was startled by the increasing frequency of the tremors."
"The station broadcasts at a frequency of 98.5 megahertz."
The plural is common when discussing multiple rates or wave values together, especially in physics and statistics.
"The receiver can tune into several different frequencies at once."
Every radio station, Wi-Fi network, and phone call you use is just a different 'frequency' — a word Latin scholars coined for crowds, long before anyone knew waves existed.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of frequency
Frequency derives from the Latin 'frequentia', which meant a crowd or throng, and by extension fullness or abundance. It entered English in the early seventeenth century, initially carrying senses related to crowdedness and repeated occurrence before acquiring its modern quantitative meanings. The same Latin root gives English the adjective 'frequent', while the broader Latin verb family behind it also produced words such as 'fluent' and 'confluence', all connected thematically to flowing and abundance.
Related word forms
How frequency is actually used
In everyday use, 'frequency' almost always refers to how often something occurs and carries no strong connotation of formality — it suits both casual and scientific registers. In physics and engineering contexts, it takes on the precise technical meaning of cycles per second (hertz), and plural forms are common when comparing different values ('the audible frequencies'). The word is used identically in British and American English.
Easily confused with frequency
'Sequency' is a rare technical term in signal processing referring to the rate of sign changes in a sequence, whereas frequency refers to cycles per unit of time — they are distinct technical concepts despite the similar sound.