Aliases: Registry operators, TLD managers
A registry is the organization managing all names ending with a given extension.
His main tasks consist of:
Keeping track of all registered domains
Defining the registration policies to agree with
Each extension is managed by one registry, but a registry may be responsible for several extensions.
Most registries do not offer registration services directly to end-users.
They work with a network of accredited providers, commonly called registrars.
When a registry also offer services directly to end-users, it is said to be acting as a registrar for such services.
The accreditation enforces the fact the registrar has a direct relationship with the registry.
Most registries publish on their website the list of their accredited registrars.
A registrar may not necessarily be accredited for all the extensions managed by a registry, as the accreditation may be on a per-extension basis rather than on a per-registry basis.
Aliases: Domain providers, Registration providers
A registrar is a provider offering domain registration services to its clients.
The clients are usually end-users but they can also be resellers, i.e. other providers who will resell the services.
Depending on the domain extension, a provider can either be an accredited registrar or acting as reseller (no direct relationship with the registry). In both cases, the provider is often simply called a registrar.
In addition to registry accreditations, a registrar may also be accredited by ICANN.
It is a global accreditation, in the sense that it is not a registry-specific accreditation. However, it is a pre-requisite in order to be accredited by some registries.
There are many registrars out here.
The largest one in terms of the number of registered domains is by far GoDaddy , managing more than 70 million domains.
Aliases: domain owners, domain holders
A registrant is actually the domain owner, i.e. the person or organization who owns a domain.
A owner has the rights to use the domains he owns.
Both owner and registrant are interchangeable terms, but we usually prefer avoid using registrant as it could easily be confused with registrar, the writing of the two words being very similar.
Be aware that a domain is not owned for ever.
The notion of "domain owner" could actually be misleading in some way.
A few registries are actually using "domain holder" instead. For instance, this is the case of DENIC, the registry for the .DE extension.
Alias: Internet Corporation for Assigned Names and Numbers
ICANN is the not-for-profit authority especially responsible for the management of the whole domain name system.
Amongst his responsibilities, ICANN maintains two lists:
The list of each registry assigned to any domain extensions.
This information is available on the IANA website:
IANA Database of Top Level Domains (middle left)
For brand extensions, i.e. extensions not open to the public such as .BNPPARIBAS, the term owner could be more appropriate than registry as all domains are exclusively registered by the brand owner.
The list of all the accredited registrars with ICANN.
This information is available on the ICANN website here .