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 of nocturnal

• night
• midnight

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

During wildlife surveys in 2022 and 2023 in eastern Thailand, a research team came across a small, nocturnal gecko with a triangular head and large, slightly protruding eyes. —Ryan Brennan, Kansas City Star, 25 Feb. 2026

The Khlong Hat bent-toed gecko may be small, nocturnal and confined to one district in eastern Thailand. —Ryan Brennan, Charlotte Observer, 25 Feb. 2026

The Khlong Hat bent-toed gecko is nocturnal. —Ryan Brennan, Miami Herald, 25 Feb. 2026

But the nocturnal and reclusive New Zealand native bird ’s fate is teetering toward survival after an unlikely conservation effort that has coaxed the population from 50 to more than 200 over three decades. —Charlotte Graham-McLay, Los Angeles Times, 24 Feb. 2026

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