What does 质量 (zhì liàng) mean in English?

Card 554HSK 2010 Level 4554/586
CARD554
PROGRESS95%
质量
質量
zhì liàng
quality; mass (in physics); CL:個|个[ge4]

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