In the Internet’s Domain Name System, the top-level domain that identifies addresses operated by four-year, degreed educational institutions. The domain name .edu appears as a suffix at the end of the address. In the United States, schools that offer kindergarten through high school classes use the top-level domain of .k12.us or just .us. See also DNS (definition 1), domain (definition 3), .k12.us, .us. Compare .com, .gov, .mil, .net, .org.