AAAA is a domain record, which is basically the IPv6 address of the server in which the domain is hosted. The IPv6 system was designed to replace the existing IPv4 system where each IP address comprises of 4 groups of decimal numbers ranging from 1 to 255 e.g. 18.104.22.168. In comparison, an IPv6 address features 8 sets of four hexadecimal numbers - which range from 0 to 9 and from A to F. The reason behind this transformation is the significantly smaller range of unique IPs that the existing system supports and also the rapid increase of gadgets which are connected to the world wide web. A good example of an IPv6 address is 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you'd like to point a domain to a web server which uses this kind of an address, you will need to create an AAAA record for it, and not the widely used A record, that is an IPv4 address. The two records have the same exact function, yet different notations are used, to identify the two types of addresses.