Source : Free On-Line Dictionary of Computing

country code
     
         Originally, a two-letter abbreviation
        for a particular country, generally used as a {top-level
        domain}.
     
        Originally, as the name implies, country codes were meant just
        for countries; but over time, country codes were allocated for
        many areas (mostly islands) that aren't countries -- such as
        Antarctica (aq), Christmas Island (cx) and Saint Pierre et
        Miquelon (pm).
     
        Country codes are based on {ISO 3166} and are used as the top
        level domain for {Internet} {hostnames} in most countries but
        hardly ever in the USA (code "us").
     
        {Latest list (ftp://ftp.ripe.net/iso3166-countrycodes.txt)}.
     
        (2003-05-02)