Salts of lemon Meaning, Definition & Usage

Definitions
  1. (Chem.), a white crystalline substance, inappropriately named, as it consists of an acid potassium oxalate and contains no citric acid, which is the characteristic acid of lemon; called also salis of sorrel. It is used in removing ink stains. See Oxalic acid, under Oxalic. Colloq.

Webster 1913