A right-handed door has the hinges on the right when it is viewed from the exterior of the room, while a left-handed door has hinges on the left. The door swings to the right for a right-handed door and to the left for a left-handed door.
A trick to determine if a door is right-handed or left-handed is to open the door to the room and stand with your back to the jamb with the hinges. If the door is on the right, it is a right-handed door. If the door is on the left, it is a left-handed door.