Proper noun

Singular Ontario

Plural -

Ontario

1. A lake between Ontario province and New York State.
2. A province in eastern Canada that has Toronto as its capital.
3. A city in California.
4. A town in Oregon.

Ontario / ɒ n ˈ t ɛər i . oʊ / is a Province of Canada located in the east-central part of Canada, the largest by population and second largest, after Quebec, in total area, (Nunavut and the Northwest Territories are larger in area, but they are not provinces.) The province's largest metropolitan area and Canada's most populous city, Toronto, is the capital city of Ontario. The national capital of Canada, Ottawa, is located in Ontario as well.

Ontario is bordered by Manitoba on its west, Hudson Bay on its north, and Quebec on its east, and by five states of the United States to its south (from west to east): Minnesota, Michigan, Ohio, Pennsylvania (Lake Erie) and New York. All but a small portion of Ontario's 2,700 km (1,677 mi) border with the United States follow inland waterways: from the west at Lake of the Woods, eastward along the major rivers and lakes of the Great Lakes/St. Lawrence River drainage system. These are the Rainy River, Lake Superior, the St. Mary's River, Lake Huron, the St. Clair River, Lake St. Clair, Lake Erie, the Niagara River, Lake Ontario, and along the St. Lawrence River from Kingston, Ontario to the Quebec boundary just east of Cornwall, Ontario.

Ontario is sometimes broken into two regions, Northern Ontario and Southern Ontario. The great majority of Ontario's population and its arable land is located in the south, mostly along the northern lakeshores of Lake Erie and Lake Ontario. In contrast, the northern three-quarters of Ontario is sparsely populated.

The province is named after Lake Ontario, which is thought to have been derived from Ontarí:io, a Huron (Wyandot) word meaning "great lake", or possibly skanadario which means "beautiful water" in the Iroquoian languages. Ontario contains about 250,000 freshwater lakes.