a province of eastern Canada, between Hudson Bay and the Great Lakes; population 12,160,282 (2006); capital, Toronto. It was settled by the French and English in the 17th century, ceded to Britain in 1763, and became one of the original four provinces in the Dominion of Canada in 1867.
Derivatives
Ontarian
adjective & noun
Ontario in other Oxford dictionaries
Definition of Ontario in the US English dictionary
