noun
jonidan division (sumo)
The second-lowest division in professional sumo, above jonokuchi and below sandanme.
彼は序二段で全勝優勝した。
He won the jonidan division championship with a perfect record.
The division directly above jonidan.
From 序 (jo, 'order' or 'preface') and 二段 (nidan, 'two steps' or 'second level'), referring to the second step in the sumo ranking hierarchy.