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

Before we get to this week’s travel news, here’s my periodic reminder to get your travel ducks in a row now if you’re jetting somewhere for the long holiday weekend next week.

From The Wall Street Journal • May 15, 2026

Edmond Halley later became famous for identifying the periodic nature of the bright comet now officially called 1P/Halley.

From Science Daily • May 13, 2026

I always look forward to his periodic columns in the sports section.

From Los Angeles Times • May 2, 2026

Concerns about the Fed’s transition or rising inflation could provoke periodic “spikes in bond volatility and/or funding market stress” but from Wilson’s perspective these will be manageable.

From MarketWatch • Apr. 27, 2026

I am awful at science, but half of the packet is just filling in the periodic table.

From "Sparrow" by Sarah Moon

Related Words

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