A form of teleporting, available from the Actions & Traits Menu under the 'General' section which allows you to return to your Home Point, or the start of the Duty/Dungeon that you're currently in, once every 15 minutes for zero cost.
The Return command, available at any time except while you or a party member is in combat, allows you to return to your "home point," which you can specify by interacting with any Aetheryte and selecting the 'Set Home Point' option.
If used while out of combat in a Duty or Dungeon, you will return to the starting point for that location.
Does not cost gil.
Cannot be used if you or the party are engaged in combat.