| English adjective: periodic | 
| 1. | periodic  happening or recurring at regular intervals | 
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 | Samples | The periodic appearance of the seventeen-year locust. 
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 | Synonyms | periodical | 
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 | Similar | annual, biannual, biennial, bimestrial, bimonthly, bimonthly, biweekly, biweekly, biyearly, biyearly, cyclic, daily, day-after-day, day-by-day, day-to-day, diurnal, fortnightly, half-hourly, half-yearly, hebdomadal, hebdomadary, hourly, midweekly, monthly, nightly, oscillating, oscillatory, semestral, semestrial, semiannual, semimonthly, semiweekly, triennial, weekly, yearly | 
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 | Antonyms | aperiodic, nonperiodic | 
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| 2. | periodic  recurring or reappearing from time to time | 
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 | Samples | Periodic feelings of anxiety. 
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 | Synonyms | occasional | 
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 | Similar | sporadic | 
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 | Antonyms | continual | 
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