AAAA is a domain name record, which is basically the IPv6 address of the web server in which the domain name is hosted. The IPv6 system was intended to replace the current IPv4 system in which every Internet protocol address is made up of four sets of decimal numbers ranging from 1 to 255 e.g. 188.8.131.52. In contrast, an IPv6 address includes 8 groups of 4 hexadecimal numbers - which range from 0 to 9 and from A to F. The reason for this change is the tremendously smaller amount of unique IPs the existing system supports as well as the fast increase of devices that are connected to the Internet. A good example of an IPv6 address is 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you'd like to direct a domain address to a server that uses this type of an address, you have to set up an AAAA record for it, not the commonly used A record, that is an IPv4 address. The 2 records have the very same function, but different notations are used, to separate the two forms of addresses.