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

The lyrics take cues from electroclash’s nocturnal storytelling, while the production mixes screeching brostep, hyperpop, hard techno, and UKG. — Kiana Mickles, Pitchfork, 17 July 2026

Keeping Lights on All Night Fireflies need plenty of dark to put on their nocturnal light show and attract the mates needed to produce the next generation of fireflies. — Lauren Landers, Better Homes & Gardens, 17 July 2026

While rain chances remain slim to none on Friday, some computer models indicate there could be some nocturnal storms Friday night into early Saturday as well as Saturday night into early Sunday. — Kansas City Star, 14 July 2026

During a stay, guests can walk through the property’s jungle trails, kayak on the water, learn about the reserve's nocturnal wildlife with the resident biologist, or make beadwork with a Wixárika artisan. — Meagan Drillinger, Travel + Leisure, 13 July 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