What does insomnia mean?
Insomnia is the medical term for persistent difficulty falling asleep or staying asleep, especially when the problem interferes with normal rest and daytime functioning. It can cause fatigue, irritability, poor concentration, and reduced performance, and it may be temporary or chronic. The word is most often used without an article when discussing the condition in general, as in “She suffers from insomnia,” while “an insomnia sufferer” is less common and more formal. In medical and psychological discussions, insomnia is distinguished from ordinary tiredness or a deliberately shortened night of sleep: it specifically involves difficulty obtaining sufficient sleep. Its Latin roots are transparent, combining the prefix in-, meaning “not,” with somnus, meaning “sleep,” so the word’s history directly reflects the condition it names.
nounA condition in which a person is unable to fall asleep or stay asleep long enough to get adequate rest. It may be occasional, acute, or chronic and can cause daytime tiredness, difficulty concentrating, and irritability.
- Difficulty falling asleep or remaining asleep, resulting in insufficient or poor-quality rest.
"She has been suffering from chronic insomnia for several months."
"Persistent stress led to insomnia and left him exhausted during the day."
"The clinic offers treatment for insomnia and other sleep disorders."
The plural is rare; insomnia is normally used as an uncountable condition.
"The study compared several types of chronic insomnias in adults."
The word insomnia literally means “not sleep”: its Latin name joins the prefix for “not” with a root meaning “sleep.”
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does insomnia come from?
Insomnia comes from Latin insomnia, meaning “sleeplessness,” formed from in-, meaning “not,” and somnus, meaning “sleep.” The English word entered use in the early 17th century, initially referring to wakefulness or sleeplessness. Its Latin root is also reflected in related English words such as somnambulism, somnolent, and somniloquy.
Related word forms
How insomnia is actually used
Insomnia is normally used as an uncountable noun. The adjective chronic is common when describing long-lasting insomnia, while acute refers to a shorter-lasting episode. In medical contexts, insomnia generally refers to sleep disturbance rather than simply spending less time asleep by choice.
Easily confused with insomnia
Insomnia is difficulty sleeping, whereas somnambulism is walking or performing other activities while apparently asleep.