- the falls of the Niagara River: in Canada, the Horseshoe Falls, 158 feet (48 meters) high; 2600 feet (792 meters) wide; in the U.S., American Falls, 167 feet (51 meters) high; 1000 feet (305 meters) wide.
- a city in W New York, on the U.S. side of the falls.
- a city in SE Ontario, on the Canadian side of the falls.
- (functioning as plural) the falls of the Niagara River, on the border between the US and Canada between Lake Erie and Lake Ontario: divided by Goat Island into the American Falls, 50 m (167 ft) high and approximately 300 m (985 ft) wide, and the Horseshoe or Canadian Falls, 47 m (158 ft) high and by some estimates well over 800 m (2625 ft) wide
- (functioning as singular) a city in W New York State, situated at the falls of the Niagara River. Pop: 78 815 (2001)
- (functioning as singular) a city in S Canada, in SE Ontario on the Niagara River just below the falls: linked to the city of Niagara Falls in the US by three bridges. Pop: 78 815 (2001)
Waterfall in western New York state and southern Ontario, Canada.