hydropericardium

noun
hy·​dro·​peri·​car·​di·​um | \ ˌhī-drō-ˌper-ə-ˈkär-dē-əm How to pronounce hydropericardium (audio) \
plural hydropericardia\ -​dē-​ə How to pronounce hydropericardia (audio) \

Medical Definition of hydropericardium

: an excess of watery fluid in the pericardial cavity