noun
: either of two potassium salts of carbonic acid:
a. : the deliquescent crystalline normal salt K 2 CO 3 that gives a strongly alkaline reaction in aqueous solution, that was obtained originally from wood ashes but is now made usually from potassium chloride (as by electrolysis to potassium hydroxide followed by carbonation), and that is used chiefly in making hard glass, soft soap, and in other ways similarly to sodium carbonate — see potash 1a
b. : potassium bicarbonate