A mark applied to a stamp to prevent its re-use. Usually referred to as a Postmark.

Students who qualify for cancellation of their students loans (see your promissory note for specific eligibility requirements) must submit a completed cancellation form with the necessary verification to the Student Loan Office for postponement of payments. Partial cancellation is granted annually after you have completed one full year of service as outlined in your promissory note. Once you have completed the year of service, you must submit a cancellation form verifying you completed a year of service in order for the appropriate percentage of your outstanding principal balance to be cancelled.