續一切經音義 1.118

1.118

尼殺曇分（梵語數法之極也或云優波尼洒陁慧菀法師音義引瑜伽大論譯為微細分如析一毛以為百分又析彼一分為百千萬分又於析分中如前析之乃至隣虛至不可析處名為鄔波尼殺曇分也）。

尼殺曇分 [upaniṣad fraction] (Sanskrit; the extreme limit in the numerical system. It is also called 優波尼洒陁 [upaniṣad]. Master Huiyuan's Pronunciation and Meaning cites the Yogācārabhūmi-śāstra translating it as 'infinitesimal fraction' (sūkṣma-bhāga). For example, splitting a single hair into a hundred parts, then splitting one of those parts into a hundred thousand million parts, and within those split parts splitting further as before, down to the paramāṇu bordering empty space, reaching the point where it can no longer be split, which is called an upaniṣad-bhāga [an infinitesimal fraction]).