What does 外流 (wàiliú) mean in English?

Card 2655HSK Level 42655/3571
CARD2655
PROGRESS74%
外流
wàiliú
drain; outflow(Verb)
Click to reveal
← Previous↑ DeckNext →

Reveal: Click/Space/Enter/↑↓/w/s/j/k•Navigate: ←→/h/l/a/d