hemothorax
noun
he·mo·tho·rax
variants:
or chiefly British haemothorax \ ˌhē-mə-ˈthō(ə)r-ˌaks, -ˈthȯ(ə)r- 
\
\
plural hemothoraxes
or hemothoraces\ -ˈthōr-ə-ˌsēz, -ˈthȯr-
\
\
Medical Definition of hemothorax
: blood in the pleural cavity