ditartaric

from The Collaborative International Dictionary of English v.0.48

Tartralic \Tar*tral"ic\, a. [From {Tartar} the chemical
   compound.] (Chem.)
   Pertaining to, or designating, an acid obtained as a white
   amorphous deliquescent substance, {C8H10O11}; -- called also
   {ditartaric}, {tartrilic}, or {tartrylic acid}.
   [1913 Webster]