1. Abbr. ON or Ont. A province of east-central Canada. Originally the western half of the old Province of Quebec, it was separated into Upper Canada in 1791 following the arrival of Loyalist settlers during the American Revolution. Reunited with Lower Canada (now Quebec) in 1841 as part of the Province of Canada, it once again became a separate province with Canada's confederation in 1867. Toronto is the capital and the largest city.

2. A city of southern California east of Los Angeles near Riverside and San Bernardino. Founded in 1882, it grew as an agricultural center.