bitartrate

from WordNet (r) 3.0 (2006)

bitartrate
    n 1: an acid tartrate; a hydrogen tartrate

from The Collaborative International Dictionary of English v.0.48

Bitartrate \Bi*tar"trate\, n. (Chem.)
   A salt of tartaric acid in which the base replaces but half
   the acid hydrogen; an acid tartrate, as cream of tartar.
   [1913 Webster]