| Castor Oil (n.) 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. Thesaurus Entries agar, aloes, aperient, bran, calomel, carminative, cascara, castor oil, cathartic, colocynth, diuretic, magnesia, mercurous chloride, mineral oil, mineral water, physic, purgative, purge, senna | ![]() |