An order is a specific group of people, where membership within the order may be restricted to those who follow particular religious beliefs or statutes (religious orders) or those who have been given certain titles or awards by the Crown (Chivalric Orders).
Orders in the SCA
Due to the SCA's policy on religion, there are no religious orders officially in the Society. However, many awards from all levels (ie. Baronial to Society) grant their recipients membership in a particular order. Most have a symbol which may or may not have been registered with the SCA College of Arms as a badge.
The best known orders are the peerage orders:
Most SCA "awards" are probably more accurately termed orders, since once you receive an award you are functionally a member - that is to say, ineligible to receive it again. Even the simple Award of Arms functions more like an order than an award.