If we want to mature and be our own thing it's also a good idea to separate ourselves from Reddit, otherwise Lemmy will always be considered a "Reddit clone" (even though it technically started as one and still is).
Since this is the "fediverse", it makes much more sense to use general terms than things specific to a platform. There's already /kbin, and there may be other link aggregator software platforms that appear in the future, and having a standardised set of vocabulary that all platforms can use makes it much easier for everyone to understand.
/kbin calls them magazines and there's sometimes been some confusion over the term and Lemmy having communities, even though they are the same thing. All the microblogging platforms on the fediverse for example just have "posts" and "boosts", there is no specific term for them like "tweets" on Twitter (there was the "toot" thing for Mastodon for a while, but it was quickly rolled back and hasn't been official for several years).
Don't forget that when you post on Lemmy, you're not posting "to Lemmy", you're posting to the wider "fediverse".
I would probably call them 'boards'. Communities is too long of a word imo and it makes it sound like the people subscribed all have some kind of shared culture or relationship. That definitely happens in some cases (there are subreddits which have built a community around them) but it's not universal.
Even back on Reddit I tended to call them groups, communities, fora, etc. Sublemmy is a cute word but I’d hate to have to say it to a nonline person, and I feel like it gives Reddit too much sway if we just migrate all the terms to this new space
When you call it what it is, a community (straight from the documentation), you dont ever have to explain what that means. When you call it a "sublemmy", that means nothing to anyone, and you have to explain it every time . I know which I prefer.
personally i like the fact that referencing a “subreddit” points to the fact that you are talking about a community that is on reddit, as opposed to the wider community around a topic. for example, if you say “i frequent the futurama community”, people will still not be sure what community you are actually talking about.
i think lemmy should have a unique name system for its communities.