When using WordPress there are a number of different user roles that may be assigned to a person. The highest user role is that of administrator, while the next highest is Editor.
An Editor can create and publish posts; however, the capabilities of the role do not stop there. In addition, Editors can modify and delete posts, including posts created by other users. In addition to being able to edit posts, they can perform edits on comments, including deleting or modifying them. Likewise, an Editor has the ability to access private posts and pages and manage the content found therein.
There are some limitations to the Editor user role, however. For example, an Editor cannot use WordPress to modify the website itself. That is to say, the Editor can manage the content found on the website, but cannot edit (or delete, or create) the website itself.
WordPress provides users with the ability to manage user roles. This means that if you feel the Editor user role has too much power, you can use WordPress to tweak the abilities of the role. Still, given the extensive abilities assigned to Editor users, it may be best to only give this designation to users you believe will not abuse their powers.