AAAA is a domain address record, that is essentially the IPv6 address of the web server where the domain is hosted. The IPv6 system was introduced to replace the present IPv4 system where each IP address is comprised of four groups of decimal digits which range from 1 to 255 e.g. 18.104.22.168. In comparison, an IPv6 address has eight groups of four hexadecimal numbers - from 0 to 9 and from A to F. The cause of this transformation is the significantly smaller number of unique IPs the existing system supports as well as the rapid increase of gadgets 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 web server that uses such an address, you will have to create an AAAA record for it, not the widespread A record, which is an IPv4 address. The two records provide the very same function, yet different notations are used, so as to differentiate the two types of addresses.