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insomnia Line breaks: in|som¦nia
Pronunciation: /ɪnˈsɒmnɪə/

Definition of insomnia in English:


[mass noun]
Habitual sleeplessness; inability to sleep.
Example sentences
  • Fact sheets are on topics such as restless legs syndrome, insomnia, and sleep apnoea.
  • Now stress and anxiety are obvious factors in causing insomnia but insomnia is insidious.
  • So you need to get checked out by a good doctor who knows something about sleep and insomnia.


Early 17th century: from Latin, from insomnis 'sleepless', from in- (expressing negation) + somnus 'sleep'.

  • somnolent from Late Middle English:

    ‘Causing sleepiness’ rather than ‘sleep’ was the early meaning of this. It goes back to Latin somnus ‘sleep’, which also provides the first element of somnambulist (late 18th century) (with ambulare ‘to walk’ the second element), and the second element of insomnia (early 17th century) ‘lack of sleep’.

Definition of insomnia in:
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