Yeah, "Hot" is just short for Hot Garbage. It's basically "New" for posts with a couple of upvotes and maybe 1 post.
I think it's a divide by zero thing where posts are weighted by activity divided by age. So a tiny amount of activity on a new post is weighted the same or more than an active post that's a few hours old.
Edit to add: Top 6 Hour seems to be where it's at for a mix of fresh content that is also active.