periodic

¹ American  

[peer-ee-od-ik] / ˌpɪər iˈɒd ɪk /

adjective

1. recurring at intervals of time.

   periodic revivals of an interest in handicrafts.

2. occurring or appearing at regular intervals.

   periodic visits by doctors to the village.

3. repeated at irregular intervals; intermittent.

   periodic outbreaks of the disease.

4. Physics. recurring at equal intervals of time.

5. Mathematics. (of a function) having a graph that repeats after a fixed interval period of the independent variable.

6. Astronomy.

   1. characterized by a series of successive circuits or revolutions, as the motion of a planet or satellite.

   2. of or relating to a period, as of the revolution of a heavenly body.

7. pertaining to or characterized by rhetorical periods, or periodic sentences.

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periodic ² American  

[pur-ahy-od-ik] / ˌpɜr aɪˈɒd ɪk /

adjective

Chemistry.

1. of or derived from a periodic acid.

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periodic British  

/ ˌpɪərɪˈɒdɪk, ˌpɪərɪəˈdɪsɪtɪ /

adjective

1. happening or recurring at intervals; intermittent

2. of, relating to, or resembling a period

3. having or occurring in repeated periods or cycles

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Other Word Forms

• periodicity
  noun
• periodically
  adverb

Etymology

Origin of periodic¹

First recorded in 1635–45; from Latin periodicus, from Greek periodikós; see origin at period, -ic

Origin of periodic²

First recorded in 1830–40; per- + iodic

Explanation

Something periodic happens only occasionally, after a "period" of time. Lunch happens every day, after 4th period, so it's safe to say it's periodic. Something periodic doesn't have to happen at regular intervals, though. The word "period" is the key to the meaning of periodic, because something periodic can happen only after a period of time. Periodic visits to the vet are a good way to make sure that your pet stays healthy. Why not just use "occasional," you ask. Good question. Periodic implies that the thing will continue to happen over and over—periodically. Like comets and victories by the Yankees. These things are reliable, if periodic.

Example Sentences

See Examples For:

periodic

Religious arguments are a periodic feature of comments on several dozen Facebook groups dedicated to opposing data center development.

From Salon ● Aug. 3, 2026

"Americans currently in the Middle East should exercise caution and heightened vigilance and should be prepared for flight cancellations, periodic airspace closures, and potential travel disruptions," the state department security alert said on Saturday.

From BBC ● Aug. 1, 2026

"Americans currently in the Middle East should exercise caution and heightened vigilance and should be prepared for flight cancellations, periodic airspace closures, and potential travel disruptions," it said.

From Barron's ● Aug. 1, 2026

The structure is a lattice located just beneath the surface of neurons and is known as the membrane-associated periodic skeleton, or MPS.

From Science Daily ● Jul. 15, 2026

At the University of Kansas, the journalism school does a periodic “media fast,” in which students aren’t allowed to use their devices for twenty-four hours.

From "A Deadly Wandering: A Mystery, a Landmark Investigation, and the Astonishing Science of Attention in the Digital Age" by Matt Richtel

Related Words

• annual
• intermittent
• monthly
• occasional
• recurrent
• recurring
• regular
• repeated
• routine
• seasonal
• sporadic
• weekly
• yearly