Meaning of Alum | Babel Free

Definitions

1. 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).
   countable, uncountable
2. A past attendee or graduate (of any gender) of a college, university or other educational institution.
   Canada, US
3. 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.
   countable, uncountable

Equivalents

Examples

“Venice also needed alum for trade, since it was the point of departure for overland transportation of alum to southern Germany and its cloth-manufacturing Free Cities.”

“A natural astringent and antiseptic, potassium alum was coveted for its medicinal and cosmetic properties.”

“With weld and cochineal, which are colouring matters the most sensible to the action of sulphate of iron, the purified alums gave us colours more brilliant, fresh, and in a slight degree lighter; while those with our common alums were all duller, and evidently of a deeper hue.”

“For similar reasons, aluminium sulphate and alums are used in dyeing cloth.[…]Normally alums are soluble in water and insoluble in alcohols.”

“In structure, the alums consist of simple ions, being not complexes, but double salts. Potash alum or potassium alum is the common alum, with the formula KAl(SO₄)₂·12H₂O) which, for convenience, may be written K₂SO₄·Al₂(SO₄)₃·24H₂O”

“1961 Spring, Anchora of Delta Gamma, Volume LXXVII, No. 3, page 59, Evanston-North Shore alums are happy to open their homes to Sigma actives for special social events.”

“You'll remember that we're starting with a list of slightly over 7,000 names that are alums (most of them over 50) that we'd like to whittle down to a manageable list of prospects.”

“All schools that last have alums, and, ancient as it was by American standards, Trinity by mid-century had thousands.”

““It breaks my heart to see them naked, undignified, shivering in the cold as they swallow our daily filth,” proclaims the woman, played by the Saturday Night Live alum Aidy Bryant.”

“While presidential elections have been marred by mudslinging since the early Republic, these USC alums deployed a particular type of dirty tricks: what became known as “ratf--king,” or the use of unscrupulous tactics to interfere with the campaigns of opponents. The tactics pioneered by members of Trojans for Representative Government and later CREEP set a precedent for the sort of organized political sabotage that has become commonplace today in a digital world, especially for Republicans.”

CEFR level