I haven't discussed some of the other editorial positions because publishers vary with their titles and job descriptions. I've presented the basic positions. Here are a few examples.
Associate editor, especially in larger houses, refers to someone who hopes to step up to the position of being called an editor or even senior editor. They probably don't edit manuscripts, but they do the scud work. The job refers to anything other than hands-on editing such as administrative work, formatting, and corresponding with the authors.
Assistant editor is another term that can mean the same as associate editor. Some houses have a managing editor who, as the title suggests, handles things to keep everything flowing on time. They may edit or function like supervisors for the editorial staff.
Editorial director is a term I encounter occasionally. The title says it. This is the top position. She may be an administrator or a senior editor. One editorial director with whom I worked was able to offer contracts to authors without going through the publications committee.