AAAA is a domain address record, that's basically the IPv6 address of the server in which the domain is hosted. The IPv6 system was introduced to replace the present IPv4 system in which every single Internet protocol address is comprised of 4 sets of decimal numbers between 1 to 255 e.g. 188.8.131.52. In contrast, an IPv6 address includes 8 sets of 4 hexadecimal numbers - from 0 to 9 and from A to F. The main reason for this change is the substantially smaller range of unique IPs which the current system supports and the fast increase of units that are connected to the Internet. An illustration of an IPv6 address would be 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you need to direct a domain name to a web server that uses this sort of an address, you need to create an AAAA record for it, not the widespread A record, that is an IPv4 address. The two records deliver the same exact function, yet different notations are used, to differentiate the two sorts of addresses.