1. the escape or leakage of fluid (such as blood or lymph) from a vessel into surrounding tissue or a body cavity
Usage: medical/anatomical term
2. an unrestrained or excessive expression of emotion, enthusiasm, or speech
Usage: often used to describe overly emotional or gushing behavior
3. something that is poured out or flows out
Usage: literal sense; less common in modern usage

Examples

• The doctor detected a pleural effusion in the patient's lungs.
• Her effusion of gratitude was so genuine that everyone felt moved.
• The teenager's effusion of excitement about the concert was impossible to contain.
• A pericardial effusion can sometimes indicate a serious heart condition.
• His effusion of praise for the new restaurant seemed exaggerated.
• The effusion of lava from the volcano continued for several days.