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

Arcturus is the brightest star in the constellation Bootes the Herdsman, although the constellation really looks more like a giant nocturnal kite with Arcturus marking the tail. —Mike Lynch, Twin Cities, 1 June 2025

There will be guided night hikes with night vision goggles to see owls, bats and other nocturnal creatures, as well as visiting ambassador animals, demonstrations, crafts and more. —Anna Ortiz, Chicago Tribune, 31 May 2025

As with everything Banksy, siting and context are chief among the avenues of investigation into the man’s intent and into his his hilariously ruthless nocturnal execution of his art. —Guy Martin, Forbes.com, 30 May 2025

In early 2007, Albany residents called local authorities with reports of typically nocturnal bats flying in broad daylight. —Lillian Ali, Smithsonian Magazine, 30 May 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