Importance, urgency and criticality
Importance: how much this contributes to your goals. Urgency: how soon it needs attention. Criticality: the consequence of missing it. A critical task can be months away; an urgent task can be low importance.
Inbox needs a decision. Ready has been reviewed. Waiting depends on someone or something. Later is deliberately parked. These organise your list; they do not complete tasks or pause reminders.