circadian
/sɚˈkeɪ.di.ən/adjective
circadian is spelled C-I-R-C-A-D-I-A-N: 9 letters and 4 syllables. It appears about once in every 1 million words in written English, the 30,017th most frequent word form (wordfreq, 2021 data). As an adjective, circadian means “Of, relating to, or showing rhythmic behaviour with a period of approximately 24 hours; especially of a biological process” (English Wiktionary, September 2026).
How many letters and syllables are in circadian?
| Letters | 9: C-I-R-C-A-D-I-A-N |
|---|---|
| Syllables | 4 (from its American pronunciation) |
| In writing | about once in every 1 million words; the 30,017th most frequent word form |
| Wrong spellings searched | none measured in search |
| Rhymes with |
Sources: letters and syllables from the English Wiktionary's hyphenation or pronunciation and the CMU Pronouncing Dictionary; written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media); rhymes and same-letter words are computed by PlainSpell from its own word list.
How common is circadian?
Circadian appears about once in every 1 million words in written English, the 30,017th most frequent word form in the list.
Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
How do you pronounce circadian?
- UK /səˈkeɪ.dɪ.ən/
- US /sɚˈkeɪ.di.ən/
- US /sɚˈkæd.i.ən/
Circadian has 4 syllables (counted from its American pronunciation in the CMU Pronouncing Dictionary).
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Recordings: LL-Q1860_(eng)-Vealhurl-circadian.wav, Wikimedia Commons (author and licence on each file's page).
What rhymes with circadian?
5 words on PlainSpell end in the same sounds as circadian from its last stressed vowel (/eɪdiən/):
Computed by PlainSpell from the pronunciations in the English Wiktionary (dump of September 2, 2026): a rhyme shares every sound from the last stressed vowel to the end; ordered by written frequency (wordfreq 3.1).
What does circadian mean?
The meanings the English Wiktionary records, quoted as written there (source below).
adjective
- 1
Of, relating to, or showing rhythmic behaviour with a period of approximately 24 hours; especially of a biological process.
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).
Circadian in Spanish, French, German and Portuguese
In the sense relating to rhythmic behavior with a period of 24 hours:
| Language | Words |
|---|---|
| French | circadien |
| German | circadian, zirkadian |
| Spanish | circadiano |
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Translations are Wiktionary's, by sense; a linked word has its own PlainSpell page.
Where does circadian come from?
From Latin circā (“around”) + diēs (“day”) + English -an. Compare circannual.
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).