/ Dictionary / Index A atelectasis: Meaning and Definition of Find definitions for: at•e•lec•ta•sis Pronunciation: (at"l-ek'tu-sis), [key] — n. Pathol. incomplete expansion of the lungs at birth, as from lack of breathing force. collapse of the lungs, as from bronchial obstruction. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: atelectasis (Thesaurus) atef-crown ateleiosis Related Content Daily Word Quiz: deleterious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language