alum
UK[ˈæləm]US[ˈæləm]
n
A white mineral salt used in medicine, dyeing, and water purification.
Etymology
The word 'alum' entered English in the late 14th century from the Old French 'alun', which itself descended from the Latin 'alūmen', meaning 'bitter salt'. The Latin term is likely derived from the Proto-Indo-European root h₂el- ('to grind'), referencing the mineral's traditional processing. The journey from a term for a processed mineral substance to its specific modern chemical definition demonstrates a straightforward borrowing where the original referent remained largely unchanged. Its meaning has specialized within scientific and industrial contexts but retains its core identity as a distinct astringent compound.
Analysis
This word is a simplex loanword. Its spelling and form were borrowed as a whole unit from Latin.
Examples
Alum is commonly used in the purification of drinking water.
The recipe calls for a pinch of alum to make the pickles crisp.
In traditional medicine, alum was applied as a styptic to stop minor bleeding.