cat ‧ a ‧ ract /ˈkætərækt/ BrE AmE noun [countable]
[ Date: 1400-1500 ; Language: Latin ; Origin: cataracta 'waterfall, castle gate that drops from above' , from Greek , from katarassein 'to strike down' , from kata- ( ⇨ ↑ cataclysm ) + arassein 'to strike' ; ]
[ Sense 1: Origin: because a cataract blocks sight like a gate coming down ]
1 . a medical condition that causes the ↑ lens of your eye to become white, so that you slowly lose your sight
2 . literary a large ↑ waterfall