Check out this great article from Belinda Pollard, readers:
5 Types of Editing for Authors
I often get asked about the different forms of editing, so here’s a summary.
First, let’s dispel a myth…
Editing is not spellchecking.
Some phases of editing might include a spellcheck, but professional editing is much bigger than that — a whole variety of tasks that help a book become the best it can possibly be.
And an important reminder…
You should always be the captain of your own manuscript.
You work in partnership with your editor, but the final choices are yours.
This is especially true at any point where you are paying the editor.
(Sometimes, you might need to negotiate with your publisher’s editor regarding particular changes, just depending on the relationship and the terms of your contract.)
How to use these definitions
These (below) are what I call the types of editing, because, well, this is MY blog. 
Put 100 editors in a room and they will discuss and debate terminology with great interest, as we all have subtle differences in how we label and organise our tasks.
Best practice is always to discover what YOUR editor means by any particular term.
For now, just get a sense of the movement through deeper changes to surface corrections, and from early in the writing to near-publication.
