1. ontario, lake in area almost equal to Wales, is the smallest and easternmost of the five great lakes of the St. Lawrence Basin, North America; it lies between the province of Ontario, Canada, and New York State; receives the Niagara River in the SW., several streams on both sides, and issues in the St. Lawrence in the NE.; on its shores stand Hamilton, Toronto, and Kingston on the N., and Oswego on the S.; canals connect it with Lake Erie and the Hudson River, and it is a busy and always open highway of commerce.
Definitions of ontario, lake
