AAAA is a domain address record, that's basically the IPv6 address of the web server in which the domain name is hosted. The IPv6 system was introduced to replace the existing IPv4 system where every single IP comprises of 4 sets of decimal numbers ranging from 1 to 255 e.g. 18.104.22.168. In contrast, an IPv6 address includes eight sets of four hexadecimal numbers - ranging from 0 to 9 and from A to F. The main reason for this modification is the considerably smaller range of unique IPs which the present system supports as well as the rapid increase of devices that are connected to the Internet. An illustration of an IPv6 address is 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you wish to point a domain to a web server that uses this type of an address, you have to create an AAAA record for it, and not the commonly used A record, which is an IPv4 address. The 2 records provide the exact same function, but different notations are used, so as to identify the two sorts of addresses.