Chànzhǐ (-)
original: 颤指
moving the fingertip(s) up and down
Literal translation: 颤: "(to) vibrate"; 指: "finger"; In »Chinese music dictionary« defined as a "fingering term", used for other musical instruments as well: 管 (guān [bell-less shawm (compare Japanese 篳篥 (Hichiriki), 二胡 (èrhú [2-stringed rebec]), 板胡 (bǎnhú [2-stringed rebec]), 筝 (zhēng [zither (= Japanese Koto)]), &c.
中国 [Zhōngguó]: 中国音乐词典。中国艺术研究院音乐研究所 «中国音乐词典» 编辑部 编 [Zhōngguó yīnyuè cídiǎn. Zhōngguó Yìshù Yánjiū Yuàn Yīnyuè Yánjiū Suǒ «Zhōngguó yīnyuè cídiǎn» biānjí bù biān; Chinese music dictionary, compiled by the Chinese Art Research Inst., Music Research Inst., "Chinese music dictionary" editorial board]. 北京 [Běijīng], 1984, p.35•1.
汉英词典 (Hàn Yīng cídiǎn) / A Chinese-English dictionary. 北京 [Běijīng], 1985, p.74 & 901.