Where does “下二段活用” come from?

下二段活用 (Japanese) comes from Japanese 下, from Middle Chinese 下.

下二段活用 (Japanese): a verbal conjugation class with the following...

Definitions

  1. a verbal conjugation class with the following...

Ancestry of “下二段活用”, step by step

下二段活用 traces back through two separate lines of ancestry.

via Japanese

StepLanguageWordMeaning
1Japanesethe below; the lower portion, end; low in degree...
2Middle Chinese

via Japanese 二段活用

StepLanguageWordMeaning
1Japanese二段活用bigrade conjugation
Every word from Middle Chinese Every word from Japanese