insomnia

American  

[in-som-nee-uh] / ɪnˈsɒm ni ə /

noun

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

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insomnia British  

/ ɪnˈsɒmnɪə /

noun

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

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insomnia Scientific  

/ ĭn-sŏm′nē-ə /

1. Chronic inability to fall asleep or remain asleep for an adequate length of time.

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insomnia Cultural  

1. A persistent and prolonged inability to sleep.

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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

• insomnious adjective

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.

Example Sentences

Struggling with headaches and insomnia, she found her voice on public television, and created a daily ritual for millions of stay-at-home moms.

From The Wall Street Journal • Apr. 9, 2026

Online marketing claims these peptides help with, among other things, weight loss, muscle-building, anti-aging, insomnia, tissue repair and sexual dysfunction.

From Salon • Apr. 4, 2026

I am very lucky in that I’m a very good sleeper and the few times in my life when I do experience insomnia, it’s infuriating to me because I am spoiled, basically.

From Los Angeles Times • Feb. 27, 2026

Feeling scared and suffering with insomnia, Fearon retired from all sport.

From BBC • Feb. 14, 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

Related Words

• restlessness