RIR
Regional Internet Registry: one of five regional bodies (ARIN, RIPE, APNIC, LACNIC, AFRINIC) that allocate IP address blocks and ASNs.
There are five RIRs (Regional Internet Registries) that divide the world between them and allocate IPv4, IPv6, and AS numbers to ISPs, hosting providers, and enterprises within their region. ARIN covers North America, RIPE NCC covers Europe and parts of Asia, APNIC covers Asia-Pacific, LACNIC covers Latin America, and AFRINIC covers Africa. Each RIR runs its own WHOIS/RDAP service exposing who owns each IP block. When dnschkr looks up an IP, the RIR data is the source of truth for the assignment, abuse contact, and country.