Definition of "potash" []

• See potassium carbonate. (noun)
• See potassium hydroxide. (noun)
• Any of several compounds containing potassium, especially soluble compounds such as potassium oxide, potassium chloride, and various potassium sulfates, used chiefly in fertilizers. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "While on this subject of caustic potash, it cannot be too often repeated that _caustic potash_ is a totally different article to _caustic soda_, though just like it in appearance, and therefore often sold as such."
• "Thus, for instance, all those salts which are formed by the combination of the sulphuric acid with any of the salifiable bases are called _sulphats_, and the name of the radical is added for the specific distinction of the salt; if it be potash, it will compose a _sulphat of potash_; if ammonia, _sulphat of ammonia_,  &c."
• "But it is commonly obtained from blood, by strongly heating that substance with caustic potash; the alkali attracts the acid from the blood, and forms with it a _prussiat of potash_."