nocturnal

adjective

noc·​tur·​nal näk-ˈtər-nᵊl How to pronounce nocturnal (audio)
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 adverb

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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Do Lights Keep Cockroaches Away? While cockroaches are nocturnal and are most active at night, keeping lights on is not a deterrent. Arricca Elin Sansone, Southern Living, 18 June 2025 As a parting gift, the goody bag was a pouch of M&Ms with a bat stamped on each, a celebration of The Bronx Zoo’s new World of Darkness exhibit featuring 25 nocturnal species. Bettina Zilkha, Forbes.com, 16 June 2025 The number of pangolins left in the world is currently unknown, as the animals are shy and nocturnal, making the counting of them very difficult. Fernando Cervantes Jr, USA Today, 10 June 2025 Sure enough, the nocturnal feather stars were subtly but consistently distinct. Aspen Pflughoeft, Miami Herald, 18 June 2025 See All Example Sentences for nocturnal

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

Time Traveler
The first known use of nocturnal was in the 15th century

Browse Nearby Words

Cite this Entry

“Nocturnal.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/nocturnal. Accessed 6 Jul. 2025.

Kids Definition

nocturnal

adjective
noc·​tur·​nal näk-ˈtərn-ᵊl How to pronounce nocturnal (audio)
1
: of, relating to, or occurring in the night
a nocturnal journey
2
: active at night
nocturnal insects
nocturnally 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 How to pronounce nocturnal (audio)
1
: of, relating to, or occurring at night
nocturnal myoclonus
2
: characterized by nocturnal activity
a nocturnal form of filariasis

More from Merriam-Webster on nocturnal

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