Background for alum

alum

/ˈæl.əm/ /əˈlʌm/

Illustration alum - Image 1

noun

An astringent salt, usually occurring in the form of pale crystals, much used in the dyeing and tanning trade and in certain medicines, and now understood to be a double sulphate of potassium and aluminium (K2SO4·Al2(SO4)3·24H2O).

Examples :

"The potter used alum to help set the dye and make the colors brighter on the clay pots. "

compound substance chemistry material medicine industry science

Illustration alum - Image 1

noun

Any similar double sulphate in which either or both of the potassium and aluminium is wholly or partly replaced by other univalent or tervalent cations.

Examples :

"The chemistry student identified the unknown crystal as an alum, noting its composition included sulfate and a mix of aluminum and potassium ions, characteristic of this class of double salts. "

compound substance chemistry material science

Illustration alum - Image 1

verb

To steep in, or otherwise impregnate with, a solution of alum; to treat with alum.

Examples :

"To strengthen the fabric, the seamstress alummed the delicate silk. "

chemistry substance material process

Illustration alum - Image 1

noun

(shortening) A past attendee or graduate (of either gender) of a college, university or other educational institution.

Examples :

""My father is an alum of Harvard University, graduating in 1985." "

person education group organization past achievement