Reddit has subreddits. What does Lemmy go with?
My personal vote is for lemmings!
Edit: I am personally leaning towards Sublemmy now. It retains the context of being a forum under the general sphere of Lemmy and the connection to Reddit lets people know immediately what Lemmy is about. Thanks to @[email protected] for the comment!
Users are called lemmings. Communities are called communities on lemmy and magazines on kbin. Communities makes more sense to me.