al.um
alum的音标和读音：
DJ音标发音： [ˈæləm]
KK音标发音： [ˈæləm]
alum的词性：
n.（名词）
1. Any of various double sulfates of a trivalent metal such as aluminum, chromium, or iron and a univalent metal such as potassium or sodium, especially aluminum potassium sulfate, AlK(SO4) 2·12H 2O, widely used in industry as clarifiers, hardeners, and purifiers and medicinally as topical astringents and styptics.
明矾，白矾：一种三价金属双硫酸盐，如铝、铬、铁和单价金属如钾或钠，特别是铝钾硫酸盐AlK(SO4) 2·12H 2O，在工业上广泛用作沉淀剂、硬化剂和净化剂，医学上用作局部收敛剂和止血剂
alum的词源：
2. Middle English
中古英语
3. from Old French
源自 古法语
4. from Latin al?men
源自 拉丁语 al?men