Oshawa (ŏsh´əwə), city (1991 pop. 129,344), SE Ont., Canada, on Lake Ontario. The production of automobiles, begun in 1907, is the leading industry, since Oshawa is the home site of General Motors of Canada. Other products include metals, glass, plastics, machine parts, furniture, leather and woolen goods, and electrical appliances. The town is on the site of a French trading post; there is now an automobile museum.