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; 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

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

Just under 100 ships have passed through the Strait of Hormuz since the start of March, according to data analysed by BBC Verify, despite periodic attacks on shipping in the area by Iranian forces.

From BBC • Mar. 19, 2026

Private-credit fund managers sometimes sell assets on the secondary market to satisfy periodic redemption requests from investors, as Blue Owl Capital and New Mountain Capital have recently done.

From The Wall Street Journal • Mar. 18, 2026

There had to be an explanation for Malfoy’s periodic disappearances, but he simply could not think what it could be.

From "Harry Potter and the Half-Blood Prince" by J.K. Rowling

Related Words

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