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

When Paul paints the same motif more than forty years later, the pose is the same, the egg is the same, but the light is nocturnal, the colors pale, clouded. —Karl Ove Knausgaard, The New Yorker, 27 Jan. 2025

Whether sculpting with spiderwebs or capturing the nocturnal peace of rural Maine, Pia’s work is a meditation on patience, co-creation with nature, and the unyielding pursuit of beauty as a form of resistance. —Alessia Glaviano, Vogue, 23 Jan. 2025

Share [Findings] The nocturnal heart rate of young men can be predicted by their female partners’ daytime feelings of intimacy or annoyance. —Rafil Kroll-Zaidi, Harper's Magazine, 22 Jan. 2025

Aotus monkeys, a genus of nocturnal monkeys, are native to Central and South America, according to the University of Wisconsin’s National Primate Research Center. —Mitchell Willetts, Miami Herald, 19 Jan. 2025

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