alum (
http://definr.com/alum)
n 1: a white crystalline double sulfate of aluminum: the ammonium
double sulfate of aluminum [syn:
ammonia alum, {ammonium
alum}]
2: a white crystalline double sulfate of aluminum: the
potassium double sulfate of aluminum [syn:
potassium alum,
potash alum]
3: a person who has received a degree from a school (high
school or college or university) [syn:
alumnus,
alumna,
graduate,
grad]
4: a double sulphate of aluminum and potassium that is used as
an astringent (among other things)