reply section; replies area
Common on Twitter and other social media; refers to the area where replies to a post are displayed.
リプ欄が荒れてしまった。
The reply section got out of hand.
リプ欄で質問に答
I answer questions in the reply section.
Abbreviation of リプライ欄 (reply section), from English 'reply' plus 欄 (column/section).