Chem., Pharm.
a colorless or white, water-soluble solid, KNaC 4 H 4 O 6 ·4H 2 O, used in silvering mirrors, in the manufacture of Seidlitz powders and baking powder, and in medicine as a laxative. Also called potassium sodium tartrate .
[ 1745-55; after LA ROCHELLE ]