A loan is money you borrow that must be paid back. With OSAP, you're borrowing the money from the governments of Canada and/or Ontario. When you pay back the loan, you will also be paying any interest on the debt.
With student loans, the interest that adds up while you're in school is paid by the federal and provincial governments. When you finish attending school, the Ontario government pays the interest on your Ontario student loan(s) for the first 6 months. Once the grace period ends, you're responsible for paying the interest on both your Ontario and Canada student loans.
NOTE: You agree to the terms and conditions of the loan when you sign your Master Student Financial Assistance Agreement (MSFAA) with OSAP.