Appointments VS. Admissions

[WP hopeful]

From what I've gathered through these threads, LOAs are assurances to an appointment.
What then, exactly, is an appointment? is it basically an admission? What is the difference, if any?

 

[America's Finest]

LOA - The academy "promising" an appointment if you meet certain conditions. Usually because you do not currently meet the requirements for admission (need nomination, medical qualification, etc.) but they want you. You can get a LOA and still not receive an appointment.

Appointment - the academy officially offering you admission. (accepting you)