What is addr?

Some articles on addr:

Blackhole Server - AS112 - Answered Zones, and private networks (RFC 1918) 10.in-addr.arpa 16.172.in-addr.arpa 17.172.in-addr.arpa 18.172.in-addr.arpa 19.172.in-addr.arpa 20.172.in-addr.arpa ...
ATS (programming Language) - Features - Dataview
... dataview array_v (a viewt@ype+, int, addr) =
Epson HX-20 - Expansion Port
... There's an "expansion unit" which contains sockets for extra RAM and ROMs which can be mapped to various areas in the address space using a DIP switch, even replacing the BASIC interpreter ROMs ... Some software distributed as ROMs were designed to be used in the expansion unit ...