ˈæl.əm əˈlʌm ɡɹæd ˈɡɹædjuət ˈɡɹædʒuɪt 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) a white crystalline double sulfate of aluminum: the potassium double sulfate of aluminum a white crystalline double sulfate of aluminum: the ammonium double sulfate of aluminum