nocturnal

adjective

noc·​tur·​nal näk-ˈtər-nᵊl 

1

: of, relating to, or occurring in the night

a nocturnal journey

nocturnal activities

2

: active at night

a nocturnal predator

nocturnal insects, such as mosquitoes

nocturnally

näk-ˈtər-nᵊl-ē 

adverb

Synonyms

• night
• nightly
• nighttime

Examples of nocturnal in a Sentence

he bought a new telescope so he could pursue his favorite nocturnal hobby of astronomy

Recent Examples on the Web

Trapdoor spiders are nocturnal and solitary hunters, emerging at night to hunt using vibration rather than vision to detect nearby prey. —Scott Travers, Forbes, 14 Dec. 2024

As typical of vampires, Court Orlok’s nocturnal circadian rhythm means much of the film takes place in the dead of night, with characters bathed in blueish moonlight. —Leah Dolan, CNN, 11 Dec. 2024

But here is a solution to that, too, which is that school districts should reconsider their start times — especially for teens whose nocturnal clocks really don’t sync well with such early schedules. —Mary Ellen Klas, Twin Cities, 11 Dec. 2024

The least nocturnal puma tracked was P-13, a female with a home range in the central and western Santa Monicas. —Lila Seidman, Los Angeles Times, 7 Dec. 2024

Word History

Etymology

Middle English, borrowed from Anglo-French & Late Latin; Anglo-French nocturnel, borrowed from Late Latin nocturnālis "for night use," from Latin nocturnus "of or occurring at night" (from noct-, nox night entry 1 + -urnus, temporal suffix, as in diurnus "of the day") + -ālis -al entry 1 — more at journal

First Known Use

15th century, in the meaning defined at sense 1

Kids Definition

nocturnal

adjective

noc·​tur·​nal näk-ˈtərn-ᵊl 

1

: of, relating to, or occurring in the night

a nocturnal journey

2

: active at night

nocturnal insects

nocturnally

-ᵊl-ē 

adverb

Etymology

from early French nocturnal, nocturnel or Latin nocturnalis, both meaning "nocturnal," derived from earlier Latin noct-, nox "night" — related to equinox

Medical Definition

nocturnal

adjective

noc·​tur·​nal näk-ˈtərn-ᵊl 

1

: of, relating to, or occurring at night

nocturnal myoclonus

2

: characterized by nocturnal activity

a nocturnal form of filariasis