(https://en.wikipedia.org/wiki/Internet_forum)An Internet forum, or message board, is an online discussion site where people can hold conversations in the form of posted messages. They differ from chat rooms in that messages are often longer than one line of text, and are at least temporarily archived.
BAHS forums are based on open-source software, phpBB (php is a programming language, BB stands for bulletin board), which is supported by a development community, via ... you guessed it ... forums.
In phpBB terminology, BAHS forums is a 'board'; the various discussions within that are forums.