Should I apply to grad school as an international or as a domestic student? (Canada, Engineering)
In most English-speaking countries (Canada, Australia, New Zealand), "domestic student" means "citizen or permanent resident of the country" - regardless of where you graduated.

Please notice this definition may be different in other countries (for example, in Germany, grad school applications by anyone who completed their undergrad in Germany are considered "domestic" for all purposes - barring, in some cases, tuition fees...).