One by one; individually; in detail — used to indicate reaching or treating each item or detail.
逐一報告するのではなく、要点だけをまとめてください。
Instead of reporting every single detail, please summarize only the main points.
彼は逐一メモを取るタイプだ。
He is the type who takes notes on every single thing.
会議の内容を逐一確認してから決めよう。
Let's check the meeting details one by one before deciding.