Editors can view, edit, publish and delete all content on a website, irregardless of the original author. If a post has been saved as pending by a user with the contributor user role, who can’t publish content on their own, a user with the editor role can publish that pending post. In addition to editing content, editors can also manage categories, tags and other taxonomies on the site. Since editors can delete content created by other users, you should only assign this user role to people who you trust to handle that responsibility.
The only standard user role more capable than editor is administrator. Users with the administrator user role have the same access to content and taxonomies as editors, but they can also change all settings on the site. On multisite installations of WordPress, the super admin also has more wide-reaching capabilities than the editor.