forum
n. countable B2 Upper Intermediate Oxford US //ˈfɔɹəm// UK //fˈɔːɹəm// fo·rum
n. a place where people can share ideas and talk about specific topics. In the digital world, it is a website where you can post messages and reply to others.
n. a medium or meeting place for the exchange of ideas and discussion. In a digital context, it refers to an online discussion site where users post messages in threads.
I found the answer to my computer problem on a tech forum.
The local council organized a public forum to discuss the new park project with the community.
While social media has largely replaced traditional message boards, specialized forums remain the primary repository for niche technical knowledge and long-form community discourse.
Usage
The plural can be either 'forums' or the more formal 'fora'.