castor oil

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun 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 The Century Dictionary.

• noun 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 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.
• Same as Palma Christi.

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

• noun the pale yellow vegetable oil extracted from the castor bean; used as a laxative and an industrial lubricant

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a purgative extracted from the seed of the castor-oil plant; used in paint and varnish as well as medically