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insomnia

American  
[in-som-nee-uh] / ɪnˈsɒm ni ə /

noun

insomnias plural
  1. inability to obtain sufficient sleep, especially when chronic; difficulty in falling or staying asleep; sleeplessness.


insomnia British  
/ ɪnˈsɒmnɪə /

noun

  1. chronic inability to fall asleep or to enjoy uninterrupted sleep

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

insomnia Scientific  
/ ĭn-sŏmnē-ə /
  1. Chronic inability to fall asleep or remain asleep for an adequate length of time.


insomnia Cultural  
  1. A persistent and prolonged inability to sleep.


Usage

What does insomnia mean? Insomnia is the inability to fall asleep or stay asleep for an adequate amount of time. Insomnia is often used casually to refer to occasional sleeplessness or a single instance of it. But in medical terms, insomnia typically refers to a condition involving a chronic inability to fall or stay asleep, meaning the inability is persistent and prolonged—it happens all the time. A person who experiences insomnia can be called an insomniac. Example: My insomnia gets worse when I’m under a lot of stress.

Other Word Forms

Derived Forms

Inflected Forms

Nouns

Etymology

Origin of insomnia

First recorded in 1685–95; from Latin, equivalent to insomn(is) “sleepless” ( in- in- 3 + somn(us) “sleep” + -is, adjective suffix) + -ia -ia

Explanation

A person who has trouble falling or staying asleep is suffering from insomnia. If after a hot bath, a glass of warm milk, and hours of counting sheep, you still find yourself lying wide awake in bed, it's time to admit you have insomnia. There's no cure for insomnia, but people with insomnia are advised to go to bed at the same time every night and to try to avoid stress. The noun insomnia was borrowed from Latin insomnis "sleepless," from the prefix in-, "not," plus somnus, "sleep." Somnus is actually related to Greek hypnos "sleep," the source of English words such as hypnosis and hypnotic.

Keep Reading on Vocabulary.com

Vocabulary lists containing insomnia

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

Magnesium is often promoted for sleep, but evidence for routine use as an insomnia treatment remains limited.

From Science Daily Jun. 6, 2026

“After meeting, he shared he suffered from insomnia and expressed interest in learning meditation, which I taught him. Our meetings, focused solely on practicing meditation, lasted about 30 minutes each,” Chopra said in the statement.

From Salon May 19, 2026

Women are now pursuing treatment for symptoms like hot flashes, brain fog, insomnia and dry, itchy skin.

From MarketWatch May 12, 2026

Clinicians call this the “prescribing cascade”: An antidepressant causes insomnia, so a sleep aid is added; a stimulant causes irritability, so a mood stabilizer follows.

From The Wall Street Journal May 10, 2026

Among the many symptoms associated with overexposure are blindness, insomnia, kidney failure, hearing loss, cancer, palsies, and convulsions.

From "A Short History of Nearly Everything" by Bill Bryson

He contemplated the black immensity pierced by a multitude of lights, without giving a thought to all the heavy slumbers, cruel insomnias, vain dreams, spoilt pleasures, and infinitely diverse miseries that a great city contains.

From Penguin Island by France, Anatole

They prattled of the dietary and idiosyncrasies of their several insomnias as though they had been so many exacting pet animals.

From Punch, or the London Charivari, Vol. 158, 1920-02-18 by Various

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