TLD — Top-Level Domain
The suffix of a domain (.gr, .com, .org). Managed by a registry.
What is a TLD
A TLD (Top-Level Domain) is the rightmost part of a domain — after the
last dot. In example.com, the TLD is .com. In
nerdtools.gr, it is .gr.
Each TLD is administered by a registry, which sets the rules (who is eligible to register, what the prices are, what dispute resolution policies apply, etc.).
TLD Categories
gTLD — Generic TLDs
Generic TLDs with no geographic restriction. The original ones:
.com— commercial.net— originally for networks, now general purpose.org— organizations.info,.biz,.name— added later
ccTLD — Country Code TLDs
Two-letter codes corresponding to countries/territories under ISO 3166:
.gr— Greece (managed by ICS-FORTH).cy— Cyprus.uk— United Kingdom.de— Germany.us,.fr,.it... and so on
New gTLD
Starting in 2013, ICANN opened up a process for thousands of new gTLDs. Examples:
.app,.dev,.tech— tech-oriented.shop,.store— eCommerce.io— popular with startups (even though it is technically the ccTLD for British Indian Ocean Territory).club,.online,.site— general purpose
sTLD — Sponsored TLDs
Restricted-use, sponsored TLDs:
.edu— US academic institutions.gov— US government agencies.mil— US military
Greek TLDs
.gr is managed by ICS-FORTH (Institute of Computer Science, Foundation for Research
and Technology – Hellas), headquartered in Heraklion, Crete. There are also:
.com.gr,.net.gr,.org.gr— open.edu.gr— educational institutions (restricted).gov.gr— public bodies (restricted).ελ— Greek IDN TLD (since 2018, with Greek characters)
IDN — Internationalized Domain Names
In the past, domains only supported ASCII characters. Today IDN exists: you can have
παράδειγμα.ελ or café.fr. Behind the scenes, Punycode encoding
is used (xn--...).