Where does “四段活用” come from?

四段活用 (Japanese) comes from Japanese 四段 — quadrigrade conjugation.

四段活用 (Japanese): a verbal conjugation class consisting of four...

Definitions

  1. a verbal conjugation class consisting of four...

Ancestry of “四段活用”, step by step

四段活用 traces back through two separate lines of ancestry.

via Japanese 四段

StepLanguageWordMeaning
1Japanese四段quadrigrade conjugation

via Japanese 活用

StepLanguageWordMeaning
1Japanese活用application; inflection; to utilize
Every word from Japanese 四段