alum
/ˈæl.əm/ noun, verb
Forms alums aluming alumed alumni alumn
- 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).
- noun (inorganic chemistry) 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.
- verb (transitive) To steep in, or otherwise impregnate with, a solution of alum; to treat with alum.
- noun (Canada, US) A past attendee or graduate (of any gender) of a college, university or other educational institution.
Synonyms
potash alum alumni alumnx ammonia alum ammonium alum potassium alum alumnus alumna graduate grad
Etymology
From Middle English alum, alym, alyme, from Anglo-Norman alum, alun, from Latin alūmen.
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).
Webster’s 1913
- noun A double sulphate formed of aluminium and some other element (esp. an alkali metal) or of aluminium. It has twenty-four molecules of water of crystallization.
- verb To steep in, or otherwise impregnate with, a solution of alum; to treat with alum. Ure.
Etymology [OE. alum, alom, OF. alum, F. alun, fr. L. alumen alum.]
Sources: Wiktionary · WordNet 3.0 · Webster’s 1913 — from the Wiktionary entry “alum”, CC BY-SA 4.0. Details