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alum

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alum¹

  • /ˈæl.əm/

Sounds like Allam

Where it comes from

From Middle English alum, alym, alyme, from Anglo-Norman alum, alun, from Latin alūmen.

noun alums · alumn

  1. countable, uncountable 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). 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.
  2. countable, uncountable 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. 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.

Similar: potash alum

verb alums · aluming · alumed · alumn

  1. transitive To steep in, or otherwise impregnate with, a solution of alum; to treat with alum. The silk should be boiled at the rate of 20 parts of soap per cent. , and then alumed. The aluming need not be so strong as for the fine crimson

alum²

  • /əˈlʌm/

Rhymes with -ʌm

Where it comes from

Clipping of alumnus and alumna (> alumn- > alum), by the removal of the originally Latin gender-specific nominative singular case endings -us (masculine) and -a (feminine).

noun alums · alumni · alumn

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

    Similar: alumni, alumnx

Thesaurus

Closest in meaning: potash alum, grad, alumnus, alumna, graduate, ammonia alum, ammonium alum, potassium alum, potash, hematoxylin, carmine, cochineal, haematoxylin, styptic, astringent, whey

noun

Similar: potash alum

Translations

Every language

noun chemistry: double sulfate

Españolalumbre
한국어명반 myeongban
日本語ミョウバン myōban, 明礬 myōban
中文明礬 /明矾 míngfán
Portuguêsalume, alúmen
Françaisalun
DeutschAlaun
Italianoallume
Ελληνικάστυπτηρία styptiría, στύψη stýpsi
Românăalaun
Русскийквасцы́ kvascý
العربيةشَبّ šabb

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

Españolalumbrar
Françaisaluner

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MLA

"alum." Wiktionary, via Micwyn, micwyn.com/word/alum. Accessed 6 Nov. 2026.

APA

alum. (n.d.). In Wiktionary, via Micwyn. Retrieved November 6, 2026, from https://micwyn.com/word/alum

Chicago

"alum." Wiktionary, via Micwyn. Accessed November 6, 2026. https://micwyn.com/word/alum.

BibTeX
@misc{alum_2026,
  title = {alum},
  howpublished = {Wiktionary, via Micwyn},
  year = {2026},
  url = {https://micwyn.com/word/alum},
  urldate = {2026-11-06}
}