n :  a strong dicarboxylic acid C₄H₆O₆ of plant origin that occurs in three optically isomeric crystalline forms : esp  :  a dextrorotatory tartaric acid that is widely distributed in plants and esp. in fruits (as grapes) both free and combined as salts and that is used chiefly in effervescent beverages and pharmaceutical preparations, in desserts and candies, in photography, in making salts and esters, and as a sequestering agent .
 
 
 
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