- Often Epsom salts. Chemistry, Pharmacology. hydrated magnesium sulfate, MgSO4⋅7H2O, occurring as small colorless crystals: used in fertilizers, the dyeing of fabrics, leather tanning, etc., and in medicine chiefly as a cathartic.
Origin of Epsom salt
1760–70; after Epsom; so called from its presence in the local mineral water
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for epsom salt
Those who would prepare a magnesia from epsom-salt, may use the following process.
That which is made with the vitriolic acid, may be condensed into crystals similar in all respects to epsom-salt.