The amateur radio organization, American Radio Relay League (ARRL), has its own definition of a country. I can't locate the exact definition on the web but in general it is stated that each discrete geographical or political entity is considered to be a country. Many of these 'countries' lack even population but are considered so for awards purposes. Hams schedule trips to put these countries on the air.

Here's the ARRL list:

http://www.arrl.org/files/file/dxcclist.txt