Pseudo-domain-style host suffix
Formerly used in addresses and site names
To designate an address or hostname connected via BITNET
.bitnet was a pseudo-domain-style suffix used in the late 1980s when identifying a hostname not connected directly to the Internet but possibly reachable through inter-network gateways. In this case, it indicated that the hostname preceding it was reachable via the BITNET network. This was one of several apparent "top-level domains" that were not actually in the Internet Domain Name System (DNS) root, but were sometimes used in addresses during the time when non-Internet networks remained in wide use.