noun
chat room
An online space for real-time text conversation; used in the context of the internet.
友達とチャットルームで話した。
I talked with my friend in a chat room.
Variant spelling with a middle dot; less common but still seen.
チャット refers to the act of chatting or a chat system in general, while チャットルーム specifically means a chat room.
Borrowed from English 'chat room'.