Noun: ammonia alum
- A white crystalline double sulphate of aluminium and ammonium
"Ammonia alum is often used as a mordant in dyeing";
- alum, ammonium alum
Derived forms: ammonia alums
Type of: Al, aluminium [Brit, Cdn], aluminum [N. Amer], atomic number 13, double salt
Encyclopedia: Ammonia alum