/ Dictionary / Index E Epsom salt: Meaning and Definition of Find definitions for: Ep'som salt" Pronunciation: [key] Often,hydrated magnesium sulfate, MgSO&multiplydot;7HO, occurring as small colorless crystals: used in fertilizers, the dyeing of fabrics, leather tanning, etc., and in medicine chiefly as a cathartic. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. epsomite Epstein Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language