quercite

from The Century Dictionary.

• noun A crystalline substance, C₆H₇(OH)₅, derived from acorns, which resembles the sugars in that it is sweet and optically active, but does not ferment with yeast or reduce metallic salts.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Chem.) A white crystalline substance, C6H7(OH)5, found in acorns, the fruit of the oak (Quercus). It has a sweet taste, and is regarded as a pentacid alcohol.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun organic chemistry A white crystalline substance found in acorns.