Main Entry: in·som·nia

Pronunciation: \in-ˈsäm-nē-ə\

Function: noun

Etymology: Latin, from insomnis sleepless, from in- + somnus sleep — more at somnolent

Date: circa 1623

: prolonged and usually abnormal inability to obtain adequate sleep

— in·som·ni·ac \-nē-ˌak\ adjective or noun