noun
circular; circulating letter; reply
Refers to a written communication sent to multiple recipients (circular) or a reply in correspondence. The 'reply' sense is less common in modern usage; 返信 is more typical.
会議の日程を回報で知らせた。
We notified everyone of the meeting schedule by circular.
取引先からの回報に目を通す。
I look over the reply from the business partner.