AAAA is a domain name record, that's essentially the IPv6 address of the server in which the domain name is hosted. The IPv6 system was introduced to replace the current IPv4 system where each IP is made up of 4 sets of decimal numbers ranging from 1 to 255 e.g. 18.104.22.168. In comparison, an IPv6 address features 8 sets of 4 hexadecimal digits - which range from 0 to 9 and from A to F. The cause of this transformation is the significantly smaller range of unique IPs that the existing system supports as well as the fast increase of products which are connected to the Internet. An example of an IPv6 address is 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you'd like to point a domain address to a web server which uses such an address, you'll have to set up an AAAA record for it, not the commonly used A record, which is an IPv4 address. The two records provide the exact same function, yet different notations are used, to separate the two sorts of addresses.