AAAA is a domain address record, that's in essence the IPv6 address of the web server in which the domain name is hosted. The IPv6 system was introduced to replace the current IPv4 system where every IP consists of four sets of decimal numbers which range from 1 to 255 e.g. 5.168.208.143. In contrast, an IPv6 address features 8 sets of 4 hexadecimal digits - ranging from 0 to 9 and from A to F. The main reason for this change is the tremendously smaller amount of unique IPs that the current system supports as well as the speedy increase of devices that are connected to the Internet. A good example 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 such an address, you'll have to create an AAAA record for it, not the widely used A record, which is an IPv4 address. The two records provide the exact same function, yet different notations are used, to identify the two types of addresses.