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

Kim Ward got her diagnosis more recently in 2022 after a nocturnal seizure. —Pamela McLoughlin, Hartford Courant, 10 Mar. 2026

Nighttime tornadoes possible Residents in the risk area should have more than one way to receive warnings and to have a plan in place, as severe storms could last into the night, including a chance of dangerous nocturnal tornadoes. —Doyle Rice, USA Today, 10 Mar. 2026

So to help you out there, this is a Blakiston’s fish owl (Ketupa blakistoni)), a nocturnal bird of prey. —New Atlas, 10 Mar. 2026

In terms of eveningwear, there was a sense of nocturnal nostalgia — designers looked at nightlife dressing from bygone eras and reimagined it for today — and, in several instances, showed it against a techno soundtrack. —Samantha Conti, Footwear News, 2 Mar. 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