insomnia

noun

in·​som·​nia in-ˈsäm-nē-ə 

: prolonged and usually abnormal inability to get enough sleep especially due to trouble falling asleep or staying asleep

chronic insomnia

Insomnia is a patient-reported problem characterized by difficulty falling asleep or difficulty maintaining sleep; ie, frequent awakenings, difficulty returning to sleep after awakenings, or awakening too early with inability to return to sleep.

—Daniel J. Buysse

Synonyms of insomnia

• restlessness
• wakefulness
• sleeplessness
• alertness

Examples of insomnia in a Sentence

has suffered from insomnia virtually his entire life

Recent Examples on the Web

Instead, women with OSA are more likely to have nightmares, wake up multiple times a night, have trouble staying asleep, and deal with insomnia, which then causes symptoms like daytime fatigue, morning headaches, and mood swings. —Katie Camero, SELF, 16 Apr. 2026

What The Research Found The study of more than 130,000 adults with chronic insomnia, presented at the American Heart Association’s Scientific Sessions 2025, found long-term melatonin users were nearly twice as likely to develop heart failure. —Allison Palmer, Fort Worth Star-Telegram, 15 Apr. 2026

What To Consider Instead For chronic insomnia, the American Academy of Sleep Medicine recommends CBT-I (Cognitive Behavioral Therapy for Insomnia) as a first-line treatment, ahead of supplements or medication. —Allison Palmer, Sacbee.com, 15 Apr. 2026

Each one-hour increase in screen time after going to bed was tied to a 59% higher chance of insomnia symptoms and 24 fewer minutes of sleep. —Allison Palmer, Charlotte Observer, 13 Apr. 2026

Word History

Etymology

Latin, from insomnis sleepless, from in- + somnus sleep — more at somnolent

First Known Use

1739, in the meaning defined above

Kids Definition

insomnia

noun

in·​som·​nia in-ˈsäm-nē-ə 

: prolonged inability to sleep

Medical Definition

insomnia

noun

in·​som·​nia in-ˈsäm-nē-ə 

: prolonged and usually abnormal inability to obtain adequate sleep especially due to difficulty falling asleep or staying asleep

called also agrypnia