I think a glossary would be very useful for newcomers. There are a lot of terms that are used very specifically in the Mill context that could mean different things for hardware people and for software people or just in general.
Although maybe it would be better to have it in a thread here, so it can grow. That would be a kludge though, since there is no wiki.
If it is really done in the forum, then the original post in the glossary thread should be the alphabetical list in kind of this format:
term – short definition
followed by posts that give longer definitions and explanations.
Maybe I just start, if there is a wiki some day this could serve as a starting point or seed.