hydrothorax

hy·dro·tho·rax

noun \-ˈthō(ə)r-ˌaks, -ˈthȯ(ə)r-\

plural hy·dro·tho·rax·es or hy·dro·tho·ra·ces \-ˈthōr-ə-ˌsēz, -ˈthȯr-\

Definition of HYDROTHORAX

: an excess of serous fluid in the pleural cavity; especially : an effusion resulting from failing circulation (as in heart disease or from lung infection)