Noah Webster's Dictionary 1. (n.) The hydroxide of potassium hydrate, a hard white brittle substance, KOH, having strong caustic and alkaline properties; -- hence called also caustic potash. 2. (n.) The impure potassium carbonate obtained by leaching wood ashes, either as a strong solution (lye), or as a white crystalline (pearlash).

Multi-Version Concordance Potash (1 Occurrence) Jeremiah 2:22 For though thou wash thee with nitre, and take thee much potash, thine iniquity is marked before me, saith the Lord Jehovah. (DBY)