1. additional examinations taken by students who failed or missed their regular exams
Usage: British English; educational context
2. additional items or materials that supplement something else

Examples

• Students who failed their finals will need to take supplementals in August.
• The university offers supplementals for those who missed exams due to illness.
• She passed all her courses except one, so she only needs to sit one supplemental.
• The textbook comes with supplementals including practice exercises and answer keys.
• The course materials include supplementals for advanced students.
• He was relieved to pass his supplementals on the second attempt.