diurnal: meaning, definition, pronunciation and examples

C1/C2
UK/daɪˈɜː.nəl/US/daɪˈɝː.nəl/

Formal, technical, literary, academic

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Quick answer

What does “diurnal” mean?

Of or during the day.

Audio

Pronunciation

Definition

Meaning and Definition

Of or during the day; occurring or active in the daytime (as opposed to nocturnal).

1. Daily; recurring every day. 2. In botany/zoology: describing flowers that open only during the day or animals active in daylight. 3. In astronomy: relating to the apparent daily motion of celestial objects.

Dialectal Variation

British vs American Usage

Differences

No significant difference in core meaning or usage. Slightly higher frequency in British academic writing in ecological contexts.

Connotations

Both variants carry formal/scientific connotations. No notable difference.

Frequency

Low-frequency word in both dialects, used primarily in technical registers.

Grammar

How to Use “diurnal” in a Sentence

[Adj.] diurnal + noun (rhythm, cycle)[Pred. Adj.] The animal is diurnal.[Adj.] subject to diurnal variation

Vocabulary

Collocations

strong
diurnal rhythmdiurnal cyclediurnal variationdiurnal animaldiurnal temperature
medium
diurnal patterndiurnal activitydiurnal changediurnal speciesdiurnal heating
weak
diurnal habitdiurnal motiondiurnal rangediurnal behaviourdiurnal shift

Examples

Examples of “diurnal” in a Sentence

adjective

British English

  • The diurnal rhythm of the tides is influenced by the moon.
  • We studied several diurnal primates in the Kenyan savannah.
  • The data showed a clear diurnal variation in air pressure.

American English

  • Most squirrels are diurnal, foraging for nuts during daylight hours.
  • The diurnal cycle of heating and cooling drives local winds.
  • The astronomer measured the diurnal motion of the stars.

Usage

Meaning in Context

Business

Rare. Might appear in technical reports (e.g., 'diurnal fluctuations in energy demand').

Academic

Common in biology, ecology, astronomy, meteorology (e.g., 'studying diurnal foraging patterns').

Everyday

Very rare. Used for precise contrast with 'nocturnal' (e.g., 'Is that bird diurnal?').

Technical

Primary domain. Describes cycles, behaviours, or phenomena tied to the day/night cycle.

Vocabulary

Synonyms of “diurnal”

Strong

circadian (specifically 24-hour cycle)quotidian (formal/literary for daily)

Neutral

dailydaytimedaytime-active

Weak

daylightday-to-day

Vocabulary

Antonyms of “diurnal”

nocturnalnightly

Watch out

Common Mistakes When Using “diurnal”

  • Using 'diurnal' to mean 'ordinary' or 'commonplace'.
  • Pronouncing it as /ˈdaɪ.ɜː.nəl/ (stress on first syllable).
  • Using it in casual contexts where 'daily' would suffice.

FAQ

Frequently Asked Questions

Yes, but it's formal. 'Quotidian' or 'daily' are more common. 'Diurnal' often implies a cycle tied to daylight.

'Nocturnal' is the direct antonym, meaning 'of the night' or 'active at night'.

No, it's a mid-to-low frequency word used mostly in scientific, academic, or formal literary contexts.

Link 'di-' to 'day' (think 'dial' for sun dial) and 'noct-' to 'night' (think 'nocturne', a piece of music for the night).

Of or during the day.

Diurnal is usually formal, technical, literary, academic in register.

Diurnal: in British English it is pronounced /daɪˈɜː.nəl/, and in American English it is pronounced /daɪˈɝː.nəl/. Tap the audio buttons above to hear it.

Phrases

Idioms & Phrases

  • The diurnal round (formal/literary: the routine of daily life)

Learning

Memory Aids

Mnemonic

DIUrnal = During the Day. Think 'DIE' (as in 'day' in Latin 'dies') + 'URNAL' sounds like 'journal' (a daily record).

Conceptual Metaphor

TIME IS CYCLE (The diurnal cycle structures our lives). LIGHT IS ACTIVITY (Diurnal creatures are metaphors for those active in 'the light of reason' or public life).

Practice

Quiz

Fill in the gap
Unlike owls, hawks are creatures, hunting primarily by sight during the day.
Multiple Choice

In which context is 'diurnal' LEAST likely to be used?