- a double sulphate of aluminum and potassium that is used as an astringent (among other things)
- a person who has received a degree from a school (high school or college or university)
Synonym: alumnusalumnagraduategrad
- a white crystalline double sulfate of aluminum: the potassium double sulfate of aluminum
Synonym: potassium alumpotash alum
- a white crystalline double sulfate of aluminum: the ammonium double sulfate of aluminum
Synonym: ammonia alumammonium alum