Word
periodic
Phoneticspe·ri·od·ic, stress on the third syllable
/ˌpɪɹiˈɑdɪk/
Definitions
01at regular intervals
B2 · Upper Intermediate
adj. happening again and again at regular times.
adj. occurring or appearing at regular intervals of time.
“The machine requires periodic maintenance to keep it running smoothly.”
“The company conducts periodic reviews of its safety protocols to ensure they remain compliant with the latest industry regulations.”
Synonyms
02repeating cycles
C1 · Advanced Science Technical
adj. having a pattern that repeats itself exactly over time.
adj. having a structure or behavior characterized by repeated cycles or periods.
“The ocean tides are a periodic movement caused by the moon.”
“The researcher observed a periodic fluctuation in the data, suggesting that the chemical reaction followed a predictable cycle every four hours.”
Antonyms
03planetary orbits
C2 · Proficiency Astronomy Technical
adj. relating to the time it takes for a planet or moon to complete one circle.
adj. pertaining to the time taken for a celestial object to complete one full revolution in its orbit.
“Comets have periodic orbits that bring them near Earth every few decades.”
“The periodic motion of the planets was first accurately described using elliptical models rather than perfect circles.”
Synonyms
04chemical acid
C2 · Proficiency Science Technical
adj. relating to a specific type of acid that contains iodine.
adj. relating to or derived from an acid of iodine in its highest oxidation state.
“The teacher explained how periodic acid is used in some laboratory tests.”
“The technician prepared a solution of periodic acid to act as an oxidizing agent in the histological staining process.”
Usage
Pronounced /ˌpɜːraɪˈɒdɪk/ (per-iodic) unlike the common word /ˌpɪəriˈɒdɪk/.
Real-World Examples
“They received periodic health education along with broad lifestyle recommendations.” “If a structure is periodic, researchers can analyze only a small portion of it and predict the behavior of the entire device.” Etymology
From French périodique, from Medieval Latin periodicus (“cyclical”), from Latin periodus (“complete sentence, period, circuit”), from Ancient Greek περίοδος (períodos, “cycle, period of time”). By surface analysis, period + -ic.
From per- + iodic.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Word family
ADJECTIVE
ADVERB
Domains
- Exam level
- CambridgeCambridgeCambridge English QualificationsThe exam suite from Cambridge University Press & Assessment, from A1 Movers up to C2 Proficiency. The benchmark names double as CEFR labels.B2 FirstIELTSIELTSInternational English Language Testing SystemThe 0–9 band test co-owned by the British Council, IDP, and Cambridge. Used for university entry, work, and migration.5.5–6.5TOEFL iBTTOEFL iBTTest of English as a Foreign Language, Internet-Based TestETS's academic English test, the standard route for US university admissions. Scored 0–120, with a 1–6 scale since 2026.1–6 scale: 4.0–4.572–94TOEICTOEICTest of English for International CommunicationETS's workplace English test, big in Japan and Korea. Listening & Reading scores 10–990 and tops out at C1.785–944
- Frequency
- Frequent
- Level
- B2 · Upper Intermediate
- Updated
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englishreference.com/q/periodic