WordReference Random House Learner's Dictionary of American English © 2026
in•som•ni•a /ɪnˈsɑmniə/USA pronunciation
n. [uncountable]
WordReference Random House Unabridged Dictionary of American English © 2026- Pathologydifficulty in falling or staying asleep, esp. when habitual.
in•som•ni•a
(in som′nē ə),USA pronunciation n.
in•som′ni•ous, adj.
- Pathology, Physiologyinability to obtain sufficient sleep, esp. when chronic;
difficulty in falling or staying asleep;
sleeplessness.
- Latin, equivalent. to insomn(is) sleepless (in- in-3 + somn(us) sleep + -is adjective, adjectival suffix) + -ia -ia
- 1685–95