AAAA is a domain record, that is basically the IPv6 address of the server in which the domain is hosted. The IPv6 system was designed to replace the existing IPv4 system in which each and every IP address is comprised of 4 groups of decimal numbers which range from 1 to 255 e.g. 18.104.22.168. In comparison, an IPv6 address includes 8 sets of 4 hexadecimal numbers - ranging from 0 to 9 and from A to F. The reason for this transformation is the considerably smaller number of unique IPs which the existing system supports and also the fast increase of products that are connected to the Internet. An illustration of an IPv6 address would be 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you want to point a domain to a server that uses this type of an address, you'll have to set up an AAAA record for it, and not the widely used A record, that is an IPv4 address. The two records have the very same function, yet different notations are used, to differentiate the two sorts of addresses.