noun
alum
AL-uhm
noun
1
A crystalline mineral salt of aluminium, traditionally used in dyeing, tanning, and as an astringent.
"A stick of alum can be used to soothe small shaving cuts."
2
Informal term for a graduate or former student of a school or college.
"Several famous alums returned to speak at the reunion."
How to Use Alum
Learner’s notesIn plain EnglishEither a mineral salt used in tanning and cooking, or a casual word for a graduate.
Common mistake
Don't confuse with "alumni," which is specifically the plural form of graduates.
Easily confused with
Word Forms
alumed past tense, alums plural, alums plural, alumni plural, alums singular
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Etymology
From Latin alumen via Anglo-Norman alum — unrelated in origin to the graduate sense, which is a modern short form of "alumnus/alumna."