What does 浓度 (nóngdù) mean in English?

Card 1856HSK Level 41856/3571
CARD1856
PROGRESS52%
浓度
濃度
nóngdù
chroma; consistency(Noun)

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