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Pronunciation: in-som'ne-a

Definition: Inability to sleep, in the absence of external impediments (noise, a bright light) during the period when sleep should normally occur; may vary in degree from restlessness or disturbed slumber to a curtailment of the normal length of sleep or to absolute wakefulness.

Synonym(s): sleeplessness

[L. fr. in- priv. + somnus, sleep]

Further information

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© Copyright 2019 Wolters Kluwer. All Rights Reserved. Review date: Sep 19, 2016.