adj ·Uncommon ·Advanced level

Definitions

Adjective

1. 1
   Of, relating to, or showing rhythmic behaviour with a period of approximately 24 hours; especially of a biological process. not-comparable

   "The circadian clock is involved in the regulation of the diurnal sleep-wake cycle, […]."

Adjective

1. 1
   of or relating to biological processes occurring at 24-hour intervals wordnet

Synonyms

All synonyms

dailydiurnaldiurnaleverydayhemeralnyctohemeral

Example

More examples

"Circadian cycles can be easily appreciated in plants."

Etymology

From the Latin circā (“about”) and diēs (“a day”) with the English suffix -an. Compare circannual.

Related phrases

circadian clockcircadian dysrhythmiacircadian rhythm

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.