LYE (נֶ֫תֶר, H6003; νίτρον). A word found in the ASV and RSV in Jeremiah 2:22 (KJV NITRE), and referring to an alkaline substance used for cleansing purposes, either sodium carbonate, found in certain places as an incrustation on the ground or in certain saline lakes, or potassium carbonate, which was obtained by leaching wood ashes or other vegetable matter. Both possess excellent detergent qualities. Niter, in its modern usage, refers to saltpeter, nitrate of potash, and is not the same as the nitron of the ancients, which was a cleansing agent, while saltpeter is useless for the purpose of cleansing.