Direct quote from Wikipedia... "coop, the top level domain used only for cooperatives on the Internet"
Yes. .coop is an existing top level domain name, which has been in existence since 2002
Mexico uses the top-level domain .mx
.is is the top-level domain for Iceland.
Its TLD - Top Level Domain.
Slovakia uses .sk as an Internet top-level domain.
Khartoum is the capital of Sudan, which uses .sd as its Internet top-level domain.
Guinea uses .gn for an Internet top-level domain.
'hr' is the top level country domain code for Croatia.
.nl is the top level domain for Netherlands.
The three parts of a domain name are the host record (www, @(none) or *(other)), the SLD (second level domain) and the TLD (top level domain) or ccTLD (country code top level domain). For example wiki.answers.com:wiki = host nameanswers = SLD (second level domain).com = TLD (top level domain)
The United-States of America TLD (Top Level Domain) is .us