From Longman Dictionary of Contemporary Englishcastor oilˌcastor ˈoil noun [uncountable] MDa thick oil made from the seeds of a plant and used in the past as a medicine to make the bowels empty
Examples from the Corpus
castor oil• Elsie and Edith Port were so alike that Jennie dosed the wrong one with her cure for all ailments - castor oil.• Similar research projects are developing plastics from materials such as corn, molasses, potato peelings and castor oil.• It seems to me that I wore glasses before I wore zinc and castor oil cream.• Caffeine enemas are given four hourly, as well as castor oil - orally or by enema - to aid detoxification.• Thatcher diktats do not simply slide down the Cabinet table like castor oil.• Madeleine said she didn't mind, but you could see his lordship was going down like a dose of castor oil.• The goods actually supplied consisted of copra cake combined with a quantity of castor oil, the latter being poisonous to cattle.• And that would get us back to castor oil and the secret police.Origin castor oil (1700-1800) Probably from castor “substance obtained from part of a beaver's body, used in medicines and perfumes” ((16-19 centuries)), from castor “beaver” ((14-19 centuries)), from Latin, from Greek kastor; because castor oil was once used instead of castor in medicines 