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

Shiva tokay geckos are nocturnal, living in and around limestone caves, the study said. —Aspen Pflughoeft, Miami Herald, 18 Feb. 2025

This is especially the case when looking for nocturnal animals at dusk or at night. —David Szondy, New Atlas, 18 Feb. 2025

As nocturnal creatures, this provides them with a comfortable space to freely roam about. —Sarah Han, Allure, 16 Feb. 2025

Are hamsters nocturnal animals? Hear a hamster rummaging in its cage at night? —Krystal Nurse, USA TODAY, 6 Feb. 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

Rhymes for nocturnal

• diurnal
• eternal
• external
• fraternal
• infernal
• internal
• maternal
• paternal
• pimpernel
• colonel
• journal
• kernel

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