It's a really good name for forum software - better than Discourse for a few reasons:
- one syllable, one easy phonetic spelling
- archaic, so it won't be confused in everyday speech
- it doesn't sound like it might do something else. Discourse could be online learning, golf venue rankings, etc.
It's used in one idiomatic expression, "the point is moot", which is almost always misused to mean 'irrelevant' rather than 'debatable'. The funny thing about idioms is that many are atomic: native speakers don't bother to dissect the individual words, they use the whole phrase because it signals something specific to other fluent speakers. When you learn a second language (French, in my case), these expressions are interesting because they usually do have an outmoded meaning, but if you ask someone they have a very hard time translating or explaining. They're also a giant pain unless you learn through immersion, because they're habitual and not usually systematic in any way.
The "archaic" usage at that link is actually very much alive, it's a technical term used in law school for mock trials [1]. I would argue law students actually understand the meaning of the term better than average, native English speakers, making the technical term less archaic.