.co (second-level domain) current manager, Neustar, markets it to global markets as an alternative to .com, or as a "generic country code top level domain" gccTLD. .co (second-level domain) In a number of countries, .co is used as a second-level domain to mean "commercial" and domain registrants register second-level domains of the form .co.xx, where xx is the country code top level domain (e.g., .co.uk in the U.K. and .co.jp in Japan). Some of the countries using .co as a second-level domain include: Barbados (.bb), Cook Islands (.ck), Costa Rica (.cr), India (.in), Indonesia (.id), Israel (.il), Japan (.jp), New Zealand (.nz), South
Top-level domain the Internet Assigned Numbers Authority (IANA), and is in charge of maintaining the DNS root zone. IANA currently distinguishes the following groups of top-level domains: domain (.arpa) Originally, the top-level domain space was organized into three main groups: "Countries", "Categories", and "Multiorganizations". An additional "temporary" group consisted of only the initial DNS domain, arpa, and was intended for transitional purposes toward the stabilization of the domain name system. As of 2015, IANA distinguishes the following groups of top-level domains: Countries are designated in the Domain Name System by their two-letter ISO country code; there are exceptions, however (e.g., .uk). This