With "Display modes" now a first-class citizen in Drupal 8, there is some lingering confusion about the various "modes" in the Drupal eco-system. In previous versions of Drupal, it could be argued that "display modes" and "view modes" were the same thing. Now that Drupal 8 is available, we should make an effort to be more precise in our definitions of these terms. 

In short, both "view modes" and "form modes" are types of "display modes":

• Display modes
  • View modes
  • Form modes

This is evident from the "Structure | Display modes" page (admin/structure/display-modes) of any Drupal 8 site:

Unfortunately, the rest of the Drupal 8 admin user interface isn't consistent with this nomenclature. For example, the "Format: Show" option of the Views module labels View modes as "Content" - which can be confusing to new users:

Wouldn't it make more sense if the "Manage Display" and "Manage form display" tabs and pages be renamed to "Manage view modes" and "Manage form modes" to make the UI more consistent?

Check out the official documentation page on Displays Modes on Drupal.org.