what is AAA?

Answer 1

Short for authentication, authorization and accounting, a system in IP-based networking to control what computer resources users have access to and to keep track of the activity of users over a network.
Authentication is the process of identifying an individual, usually based on a username and password. Authentication is based on the idea that each individual user will have unique information that sets him or her apart from other users.
Authorization is the process of granting or denying a user access to network resources once the user has been authenticated through the username and password. The amount of information and the amount of services the user has access to depend on the user's authorization level.
Accounting is the process of keeping track of a user's activity while accessing the network resources, including the amount of time spent in the network, the services accessed while there and the amount of data transferred during the session. Accounting data is used for trend analysis, capacity planning, billing, auditing and cost allocation.

AAA services often require a server that is dedicated to providing the three services. RADIUS is an example of an AAA service.

Answer 2

In what context?

There is a battery type known as AAA.

An AAA battery (pronounced "triple A") is 44.5 mm long and 10.5 mm in diameter, weighing around 11.5 grams. Output of alkaline batteries in this size is 1.5 volts, 900 to 1,155 mA·h (3240 to 4158 coulombs). Modern nickel metal hydride (NiMH) batteries of this size can store about 800 mA·h, with an output of 1.2 volts.

Answer 3

Automobile Association of America

Answer 4

Amateur Athletics Association in the UK