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

In a 2023 randomized trial, 113 adults with insomnia symptoms spent five weeks in one of two groups. — J. David Creswell, The Conversation, 6 Oct. 2026

Lindsay Clancy’s case began with a bout of insomnia and anxiety several months after the birth of her third child with her husband, Patrick, in a quiet suburb outside Boston. — Eric Levenson, CNN Money, 4 Oct. 2026

In one study, researchers observed that three months of supplementation with magnesium, melatonin, and vitamin B complex, taken about one hour before bed, may help treat insomnia. — Emmanuella Ogbonna, HEALTH, 2 Oct. 2026

Research shows that side effects may include insomnia, jitteriness, and gastrointestinal issues. — Carrie Madormo, Verywell Health, 2 Oct. 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