The Collaborative International Dictionary of English v.0.48:

Quercitannic \Quer`ci*tan"nic\ (kw[~e]r`s[i^]*t[a^]n"n[i^]k), a.
   [L. quercus an oak + E. tannic.] (Chem.)
   Pertaining to, or designating, a tannic acid found in oak
   bark and extracted as a yellowish brown amorphous substance.
   [1913 Webster]