from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A yellowish-red crystalline substance related to anthracene and obtained from opianic acid.
from the GNU version of the Collaborative International Dictionary of English
- n. A yellowish red crystalline substance related to anthracene, and obtained from opianic acid.
from The Century Dictionary and Cyclopedia
- n. A yellowish-red crystalline substance, (OH)2C6H2(CO)2C6H2(OH)2, or tetrahydroxyanthraquinone, made by heating opianic acid to 180° C. with concentrated sulphuric acid: used as a dyestuff.
Latin rufus reddish + opianic (Wiktionary)