alum
UK: ˈæləm | US: ˈæləm
n. 1. A chemical compound (hydrated double sulfate of aluminum and another metal, typically potassium), used in dyeing, tanning, and medicine.
n. 2. (Informal) Short for "alumnus" or "alumna," a graduate or former student of a school, college, or university.
The word "alum" originates from the Latin alumen, meaning "bitter salt," referencing its astringent taste. The morpheme al derives from aluminum, the metallic element central to the compound, while -um is a suffix commonly used in chemical nomenclature. Over time, "alum" also became a colloquial abbreviation for "alumnus/alumna," borrowing from the Latin alere (to nourish), reflecting the nurturing role of educational institutions.
The leather was treated with alum to make it more durable.
She used alum as a natural deodorant due to its antibacterial properties.
As an alum of Harvard, he frequently donates to the university.
The recipe called for a pinch of alum to crisp the pickles.
The chemistry class synthesized potassium alum in the lab.