nocturnal

adjective

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

Synonyms of nocturnal

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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.
Thanks to all these survey techniques, Arizona scientists are making inroads in illuminating the secret lives of these nocturnal critters. — Shi En Kim, AZCentral.com, 28 Aug. 2026 By Ryan Spencer, Summit Daily As millions of birds start to head south for the winter, Coloradans are turning off outdoor lights to help darken the path for these nocturnal migrators. — The Summit Daily, Denver Post, 26 Aug. 2026 The Texas Parks and Wildlife Department even specifically promotes nighttime hog hunting, noting that the animals become increasingly nocturnal during the hot summer months. — Amber Harding Outkick, FOXNews.com, 24 Aug. 2026 Sometimes called honey bears, kinkajous are nocturnal and live in trees. — Amy McDaniel, Fort Worth Star-Telegram, 21 Aug. 2026 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

Rhymes for nocturnal

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Browse Nearby Words

nocturn
nocturnal
nocturnality
See all Nearby Words

Cite this Entry

“Nocturnal.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/nocturnal. Accessed 2 Sep. 2026.

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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
-ᵊl-ē How to pronounce nocturnal (audio)
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
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