AOB is a short way of writing any other business. At a meeting, people follow a list of subjects. AOB is the last heading: things that were not on that list, but that someone still wants to talk about before everyone stands up. You say the three letters, A-O-B. Though actually, this is very British office, school-governor, and club English. You see it at the bottom of an agenda. A careful chair keeps AOB short, because if you are not careful it becomes a second meeting, or the place where an awkward extra request appears. It is not a company, and it is not a medical term. In a Taiwan meeting the same slot is often called 其他事項 or 臨時動議: leftover talk, not a new official topic with papers prepared.