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

• periodically adverb
• periodicity noun

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

While we all need periodic reminders that pierce through the monotony and horrors of the day, awe of nature and our fragile existence being paramount, we also need reminders that a better future is possible.

From Salon • Apr. 7, 2026

"I like the fact that in space, we are committed to bold goals to the extent that we will not let periodic failure stop our forward progress," he said.

From BBC • Apr. 2, 2026

That is the quarterly limit investors agreed to when they committed their capital to the nontraded fund, which provides periodic liquidity by repurchasing some investor shares.

From Barron's • Apr. 2, 2026

The explanation traces back to work by the French mathematician Gaston Floquet, who showed in the 19th century that systems exposed to periodic forces can develop entirely new oscillation states.

From Science Daily • Mar. 27, 2026

An article in the newspaper announced that hall patrols by federalized National Guardsmen would be eliminated, although they would remain in the building and make periodic checks.

From "Warriors Don't Cry: A Searing Memoir of the Battle to Integrate Little Rock's Central High" by Melba Pattillo Beals

Related Words

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