ameliorator
(əˈmiːlɪəˌreɪtə(r))
[f. ameliorate + -or, after L. analogies; cf. arbitrator.]
He who, or that which, ameliorates.
| 1865 Buckman Sc. in Farm Cult. xi. 74 The admixture of manures or ameliorators, such as guano. 1872 Yeats Growth & Viciss. Comm. 272 The ameliorator of agricultural distress was Fran{cced}ois. 1877 W. Thomson Voy. Challenger I. ii. 121 Our beneficent ameliorator, the Gulf-stream. |