[der-is] 
| any East Indian plant belonging to the genus Derris, of the legume family, esp. D. elliptica, the roots of which contain rotenone and are used as an insecticide. |
| der·ris (děr'ĭs) n. Any of various usually woody vines of the genus Derris of tropical Asia, whose roots yield the insecticide rotenone. [New Latin, genus name, from Greek, covering; see der- in Indo-European roots.] |
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