a.k.a. TLD, gTLD, generic top-level domain, strings, domain name ending, domain names
Two letter domains, such as .uk, .de and .jp (for example), are called "country code top-level domains" (ccTLDs) and correspond to a country, territory, or other geographic location. The rules and policies for registering domain names in the ccTLDs vary significantly and some are reserved for use by citizens of the corresponding country.
Historical perspective: From March 1985 to March 2015, more than 284 million domain names were registered and as of March 2015, there are more than +800 different domain endings to choose from. Below is an infographic of all the domain names to choose from - we realize it doesn't fit, see the full version here: http://blog.europeandomaincentre.com/infographic-know-domain-endings-com-whatever/
NetLingo Classification: Technical Terms