The (powdered) bark of any of several species of cinchona tree (genus Cinchona), containing the alkaloids quinine and cinchonine and used to treat malaria and other fevers.
Origin
Late 18th century.
Definition of grey bark in US English:
grey bark
(USgray bark)
noun
The (powdered) bark of any of several species of cinchona tree (genus Cinchona), containing the alkaloids quinine and cinchonine and used to treat malaria and other fevers.