As I know it we up here refer to Domestics as home grown North American cars. Like some of you said built in the U.S.A or Canada.
We also refer to to other countries cars outside of North America as Imports.
That is the only reason. Now some will say Toyotas are built in Canada, that is right but when the term arrived there were none built they were all overseas.
I guess the easy way is the big three GM, Ford and Chrysler are domestic and all others are imports. Savey.