| 释义 |
WordReference Random House Learner's Dictionary of American English © 2024al•um1 /ˈæləm/USA pronunciation n. [uncountable]- Chemistrya white, crystal-like salt used in medicine, dyeing, and tanning.
a•lum2 /əˈlʌm/USA pronunciation n. [countable] Informal.- Informal Termsan alumna or alumnus.
WordReference Random House Unabridged Dictionary of American English © 2024al•um1 (al′əm),USA pronunciation n. [Chem.]- ChemistryAlso called potash alum, potassium alum. a crystalline solid, aluminum potassium sulfate, K2SO4·Al2(SO4)3·24H2O, used in medicine as an astringent and styptic, in dyeing and tanning, and in many technical processes.
- Chemistryone of a class of double sulfates analogous to the potassium alum, as aluminum ammonium sulfate, having the general formula R2SO4·X2(SO4)3·24H2O, where R is a univalent alkali metal or ammonium, and X one of a number of trivalent metals.
- Chemistry(not in technical use) aluminum sulfate.
- Latin alūmini- (stem of alūmen)
- OWelsh (compare MWelsh elyf)
- Latin alūmen; replacing Old English alefne, ælifnæ
- Anglo-French
- Middle English 1275–1325
- Informal Termsan alumna or alumnus.
alum., [Chem.]- Chemistryaluminum.
Collins Concise English Dictionary © HarperCollins Publishers:: alum /ˈæləm/ n
Also called: potash alum a colourless soluble hydrated double sulphate of aluminium and potassium used in the manufacture of mordants and pigments, in dressing leather and sizing paper, and in medicine as a styptic and astringent. Formula: K2SO4.Al2(SO4)3.24H2O- any of a group of isomorphic double sulphates of a monovalent metal or group and a trivalent metal. Formula: X2SO4.Y2(SO4)3.24H2O, where X is monovalent and Y is trivalent
Etymology: 14th Century: from Old French, from Latin alūmen |