TLDs (Top Level Domains) are technically the suffix (the letter after the domain name) of a URL address, e.g. www.domain-name.com or www.domains.co.za.
In the first instance the TLD is ‘com’ and in the second it is ‘za’ representing a Country Code, ‘za’ represents South Africa’s ccTLD.
They come in various groups:
– gTLDs (Generic Top Level Domains), which are usually 3 or more letters in length – the ICANN list of current gTLDs.
– ccTLDs (Country Code Top Level Domains), these are 2 letters and are generally based on the ISO 3166 code – ICANN list of ccTLDs.
– geoTLDS (Geographic Top Level Domains), these are associated to countries and cultures – ICANN list of geoTLDs.