/ Dictionary / Index H hydrothorax: Meaning and Definition of Find definitions for: hy•dro•tho•rax Pronunciation: (hī"dru-thôr'aks, -thōr'-), [key] — n. Pathol. the presence of serous fluid in one or both pleural cavities. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: hydrothorax (Thesaurus) hydrothermal vent hydrotropic Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language