È’ěrtài 鄂爾泰 (Manchu: Ortai, 1677–1745), zì Yì’ān 毅菴, posthumously Wénduān 文端, was a leading Yōngzhèng-Qiánlóng-court Manchu official. Of the Xīlínjuéluó 西林覺羅 lineage. Rose under Yōngzhèng to Xībǎoyīnfú dàxuéshì 武英殿大學士 and Chancellor; central to Yōngzhèng’s gǎi tǔ guī liú 改土歸流 frontier-administrative reforms in YúnGuì in the 1720s. Co-supervised the imperial Qīn dìng shòu shí tōng kǎo 欽定授時通考 (KR3d0010) with Zhāng Tíngyù under Qiánlóng. Biography: Qīng shǐ gǎo j. 288.