This plastic toy has better flame resistance because diphenyl was added to it.

diphenyl 是由前缀 di-（表示"二、双"）和 phenyl（"苯基"）组成的化学名词。di- 来自希腊语，表示"两个"；phenyl 指苯环去掉一个氢原子后形成的基团。diphenyl 即"二苯基"，指由两个苯基组成的化合物。