What term should be used when defining a page in the admin menu that allows you to change a plugins options?
Options API deals with saving and retrieving options from database. So its scope and scope of "options" in terminology is that of purely storage.
Settings API deals with admin pages, forms, receiving/validating/sanitizing data, and finally using Options API to store it. So in terminology it refers more or less to level of admin interface and user interaction.
Depending on nature of your plugin its page should be named either after its own name or after what plugin does. Then it should be nested appropriately in a level such as Settings or Appearance. Creating top level pages for the plugins is not uncommon, but is often considered overblown and annoying, especially so if the plugin/theme doesn't have many things to put there.
You should just use the name of the plugin. No need to concatenate "options" or "settings" to it.
A lot of times (if the plugin is small, or you rarely need to change it's settings) you place the plugins admin page under the "Settings"-page that already exists.