What does somnolence mean?
Somnolence is a formal noun for sleepiness or drowsiness. It can describe an ordinary urge to sleep, as after a long journey or a heavy meal, but it is especially common in medical and pharmacological contexts, where excessive somnolence may be a symptom or a side effect. The word can also mean a general tendency to sleep. In ordinary conversation, people more often say sleepiness or drowsiness, but somnolence gives these ideas a more precise, professional tone. Its related adjective, somnolent, is useful for describing a person, condition, or medicine associated with unusual sleepiness. Although relatively uncommon, somnolence comes from the Latin language of sleep and dreams and belongs to the same word family as insomnia, somnambulism, and somnolent.
nounSleepiness or drowsiness, especially as a state that is noticeable or unusual. The word can also refer to an inclination or tendency to sleep.
- Sleepiness or drowsiness, especially when it is pronounced or conspicuous.
- A tendency or disposition to sleep.
"A heavy lunch and the warm afternoon air induced a profound somnolence."
"The medication was prescribed because the patient suffered from excessive somnolence."
"Her initial somnolence disappeared as soon as the conversation became animated."
Rare, because somnolence is normally used as an uncountable abstract noun.
"The report recorded separate somnolences associated with two of the medications."
Somnolence is the formal name for the feeling of being unable to keep your eyes open.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does somnolence come from?
Somnolence comes from Latin somnolentia, a noun derived from somnolentus, meaning sleepy or drowsy. The Latin root somnus means sleep and also underlies English forms such as insomnia and somnambulism. The English word entered use as a formal medical and literary term for drowsiness or sleepiness.
Related word forms
How somnolence is actually used
Somnolence is formal and chiefly medical or literary. In everyday speech, sleepiness or drowsiness is more usual. The related adjective somnolent is often used in clinical descriptions of medicines and medical conditions.
Easily confused with somnolence
Somnolence is the noun meaning sleepiness or drowsiness, whereas the related adjective somnolent describes someone or something that is sleepy.
Somnolence is a state of sleepiness, while insomnia is a condition characterized by difficulty falling or staying asleep.