a colorless to pale yellow, viscid liquid, usually obtained from the castor bean by a pressing process: used as a lubricant, in the manufacture of certain soaps and creams, and in medicine chiefly as a cathartic. Also called ricinus oil .
[ 1740-50; castor (perh. var. sp. of CASTER) + OIL; perh. so called because of its purgative effect ]