nocturnal
nok-TUR-nuhl
/nɒkˈtɜːn.əl/
Done, occurring, or active during the night rather than during daylight hours.
Describes behavioral rhythms where activity peaks after sunset.
The story behind the word. Traces directly to Latin 'nocturnus', an adjective built on 'nox' (genitive 'noctis'), meaning night. The same root 'nox' gives us 'equinox' (equal night and day) and 'nocturne' (night music).
Word relationships
- night-active: Night-active is descriptive; nocturnal is the formal ecological term.
- diurnal: Diurnal animals are active during daytime hours.
- crepuscular: Crepuscular animals are active primarily during dawn and twilight.
Commonly confused with
- diurnal: Diurnal means active by day, whereas nocturnal means active by night.
Word family
- nocturnally (adverb): In a nocturnal manner.
Collocations
- nocturnal habits
- nocturnal predator
- nocturnal creature
- strictly nocturnal
Example sentences
- "Owls are famously nocturnal predators that rely on exceptional dark vision and acute hearing to hunt at night." Animal behavior
- "Many desert species remain nocturnal to avoid the scorching heat of daytime sun exposure." Ecology
Memory hook
NOCTurnal relates to NOX (night) or turning off the light to sleep at night. Nox = night -> nocturnal.
When not to use
Do not use to describe animals active during the daytime (diurnal) or twilight (crepuscular).
Fun facts
- Nocturnal animals often have a reflective layer behind their retina called the tapetum lucidum, which makes their eyes glow in dark photo flashes!
Explore more words
sedentary, terrestrial, seasonal, habitual, around the clock, daily
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