from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A colorless or pale yellowish oil extracted from the seeds of the castor-oil plant, used pharmaceutically as a laxative and skin softener and industrially as a lubricant.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. the pale yellow vegetable oil extracted from the castor bean; used as a laxative and an industrial lubricant
from the GNU version of the Collaborative International Dictionary of English
- A mild cathartic oil, expressed or extracted from the seeds of the Ricinus communis, or Palma Christi. When fresh the oil is inodorous and insipid.
from The Century Dictionary and Cyclopedia
- n. The oil yielded by the seeds of Ricinus communis (the castor-oil plant), a native of India, but now distributed over all the warmer regions of the globe.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a purgative extracted from the seed of the castor-oil plant; used in paint and varnish as well as medically
Possibly from a former use as a substitute for castor in medicine.(American Heritage® Dictionary of the English Language, Fourth Edition)