Domain Glossary

When creating a website or setting up email, you’ll often come across terms like “domain,” “DNS,” or “nameserver.” But what do they actually mean, and how do they relate to each other? Here are some simple explanations – no technical background needed.

• Domain
• TLD
• Registry
• Registrar
• WHOIS
• RDAP
• Renewal & Expiration
• ICANN
• DNS (MX, A, CNAME etc)
• Nameservers
• Auth-ID
• Ownership (Registrant)
• Ascio
• NIS2
• Domain Lock

Domain

A domain is the web address people type to visit your website.
For example: mycompany.com

It’s like your home address - but for your site or email.

A domain has three parts:

• www – a common prefix, but not always needed
• Name – like mycompany
• Ending – like .com, .no, or .net (called a TLD)

Why are some domains different?

Domains can vary in:

Price – some costs more to register or renew

Rules – some require a local address or company info

Style – .no feels local, .com feels international

Availability – some names are already taken

Tip: Choose a domain that’s easy to remember and fits your brand.

TLD

The TLD (top-level domain) is the part after the dot, like .com or .no.
Different endings mean different things:

• .com – popular worldwide
• .no – for Norway
• .net, .org – also common
• .dk, .de, .eu – for Denmark, Germany, the EU, and so on

Some endings are local (like .no), others are global (like .com).

Read more: What is a top-level domain?

Registry

Each domain is managed by a special organisation called a registry (sometimes also called a NIC)
They decide the rules for who can register a domain and how it's managed.

Here’s a list of common domain endings (TLDs) in Europe:

Here is a list of all the TLDs one.com offers.

Registrar

A company (like one.com) where you register, manage, and renew your domain name.
It acts as the link between you and the registry.

Read more: What is a registry, registrar and registrant?

WHOIS

A public database that shows details about a domain, such as who owns it and when it expires.
For privacy, some of this information can be hidden.

Read more: What is WHOIS?

Renewal & Expiration

Domains are usually paid for one year at a time.
To keep your domain active, you need to renew it before it expires.

If you don't renew it, the domain will expire. Your website and email may stop working, and someone else could register your domain.

Read more: Understanding the life cycle of a Domain

ICANN

The global organisation that coordinates domain names and IP addresses.
They make sure the Domain Name System (DNS) works smoothly worldwide.

Read more: What is ICANN?

RDAP

RDAP is a newer version of WHOIS. It shows information about who owns a domain and where it’s registered.

It’s more secure and structured than WHOIS, and it can handle privacy rules (such as GDPR).

You may see RDAP results when you look up domain ownership online.

DNS 

This system connects your domain name to the server where your website and emails are stored.

It works like the internet’s address book - turning names into numbers (IP addresses).

Common DNS records are:

• A
• SPF
• TXT
• CNAME
• Web Forward
• MX

And many more.

Read more: What is DNS?

Nameservers

Nameservers are part of your domain’s DNS settings. The nameservers you use determine where you manage your DNS records. They tell the internet where to find your website or deliver your email.

The nameservers one.com is using are:
ns01.one.com
ns02.one.com

Read more: How do I change the name servers?

Auth-ID

An Auth-ID (also called Auth code or EPP code) is a unique password used when you transfer a domain to a new provider.

It’s like a security key - it proves that you own the domain and gives permission to move it.

Read more: Where do I find my Auth-ID/EPP code?

Ownership (Registrant)

Ownership means who legally controls the domain - usually a person or company. The owner is also called registrant.

If you own the domain, you can change settings, transfer it, or connect it to a website or email.

Make sure your contact details are correct, so you don’t lose access or miss important renewal reminders. 

Read more: 
Change the domain owner's contact details
Change the owner of your web space and domain
 

Note: The domain owner might be different from the person who owns the web hosting.
Read more:
What is the difference between the subscription owner and the domain owner?

Ascio

Ascio is a domain registrar that works behind the scenes with companies like one.com.

If your domain is managed through Ascio, you might see their name listed in WHOIS or RDAP lookups - that’s normal.

They help handle the technical part of domain registration and transfers.

NIS2

NIS2 is an EU law that sets stricter rules for online security, including domain registrations.

It may require domain owners to provide accurate contact information, which could affect how WHOIS or RDAP data is shown.

The goal is to improve cybersecurity and make it harder to misuse domain names.

Read more: NIS2 Directive: securing network and information systems

Domain Lock

Domain Lock protects your domain from unauthorised transfers and changes to ownership details.
It adds an extra layer of security, but you can still update DNS settings and use your domain as usual.

You can turn it on or off in the one.com Control Panel.

Read more: Domain Lock

Related articles:

• Understanding the life cycle of a Domain
• Manage your DNS settings