What does 血汗 (xuèhàn) mean in English?

Card 1783HSK Level 31783/2202
CARD1783
PROGRESS81%
血汗
xuèhàn
blood-vessel; blood vessel(Noun)

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