1. graduates or former students of a school, college, or university
Usage: plural of alumnus/alumna
2. chemical compounds containing aluminum and sulfur, used in various industrial processes
Usage: chemistry; plural of alum

Examples

• The university invited alums to the homecoming celebration.
• Many alums donate money to their former schools.
• The college newsletter keeps alums informed about campus news.
• Several alums returned to speak at graduation.
• The chemistry lab stored various alums for experiments.
• These alums are used in water purification processes.