Huáyīn (-)
original: 滑音
moving a finger gradually in order to "glide" from one tone to another
Literal translation: 滑: "slippery / smooth"; 音: "sound / tone"; Portamento; ➺ Shànghuáyīn, Xiàhuáyīn.
Wong, Samuel Shengmiao: Qi’ - An instrumental guide to the Chinese orchestra. Singapore, 2005, p.139, 143.
汉英词典 (Hàn Yīng cídiǎn) / A Chinese-English dictionary. 北京 [Běijīng], 1985, p.288 & 826.