* The Dialing Country Code is the prefix number you have to dial to connect your call to the specific country you want to call.
** The International Call Prefix (also called an international access code or an International Direct Dialing code - IDD) is a telephone dialing code used to dial out of a country when making an international call. In given phone numbers the IDD is often abbreviated by just "+" like in +0123 456 789, to signify that the caller should use the appropriate prefix for the country from where he is calling.
*** National Code (like an Area Code) is the local number within the North American Numbering Plan (NANP) related to island nations and US dependencies in the Caribbean and the South Pacific.