AAAA is a domain address record, that is essentially the IPv6 address of the server where the domain is hosted. The IPv6 system was introduced to replace the present IPv4 system in which every IP is comprised of four sets of decimal digits which range from 1 to 255 e.g. 18.104.22.168. On the other hand, an IPv6 address includes eight groups of four hexadecimal digits - ranging from 0 to 9 and from A to F. The main reason for this change is the substantially smaller number of unique IPs which the existing system supports and the quick increase of units that are connected to the world wide web. An illustration of an IPv6 address would be 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you'd like to direct a domain address to a web server which uses this type of an address, you will have to create an AAAA record for it, and not the commonly used A record, which is an IPv4 address. The 2 records have the exact same function, but different notations are used, to distinguish the two forms of addresses.