Wiktionary
country code
n. A short alphabetic or numeric geographical code representing a specific country or area.
Wikipedia
Country code
Country codes are short alphabetic or numeric geographical codes ( geocodes) developed to represent countries and dependent areas, for use in data processing and communications. Several different systems have been developed to do this. The best known of these is ISO 3166-1. The term country code frequently refers to international dialing codes, the E.164 country calling codes.