from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An allelopathic aromatic compound found in the leaves, roots, husks, and bark of plants in the Juglandaceae family, particularly the black walnut, used as a colouring agent.
from the GNU version of the Collaborative International Dictionary of English
- n. A yellow crystalline substance (C10H6O3) resembling quinone, extracted from green shucks of the walnut (Juglans regia); -- called also nucin. Chemically, it is 5-hydroxy-1,4-naphthalenedione.
from The Century Dictionary and Cyclopedia
- n. A yellowish- or brownish-red compound, HOC10H5O2. prepared by the oxidation of a-hydrojuglone from the green parts of the walnut-tree; a-hydroxynaphthoquinone, nucin, or regianin. It crystallizes in needles or prisms and melts at 151–154° C.
Juglandaceae and -one. (Wiktionary)