Post History

There are other types of posts (and other types of top-level posts).

In a comment you mentioned the category bar that contains "posts", "tags", and "edits".  This has to work on all categories on all communities.  While every community has categories where all top-level posts are questions, some have other post types like articles.  See, for example, Papers on Electrical Engineering, Recipes on Cooking, and Blog here on Meta.

You might then think that ok, we could use "questions" for the Q&A categories and "posts" or "articles" for those other categories, but there are two issues there: first, a category can include more than one top-level post type (questions *and* articles, for example), and second, more post types can be created through the UI (not baked into the code).  Rather than trying to choose the right word for each category on each community, we use "posts" which is true everywhere.

You also mentioned URLs.  Post-type-specific URLs actually work; you can access this question using https://meta.codidact.com/questions/286465 (which is then rewritten to the "post" URL).  Originally all our post URLs embedded the type like that but, again, it wouldn't work for new post types.  There are still places in the code that hard-wire the idea that questions, answers, and articles are the only post types (the stats on the profile page, for instance), but this is technical debt, not the desired design.  We've created one new post type through the UI (wiki) already and people have talked about others.  There will be more post types, almost certainly.