Top-level domain
The label directly beneath the DNS root.
.com · .org · .ke
Domain anatomy
Parts of a domain name
A domain name is a sequence of labels separated by dots. The labels form a hierarchy: the rightmost visible label is the TLD, the registered name sits beneath it, and optional subdomains extend to the left.
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The core concept
Dots mark hierarchy boundaries
Human readers scan left to right, but DNS authority becomes broader as you move right.
blogSubdomain
›
exampleRegistered label
›
comTLD
A fully qualified DNS name can be written with a final dot—blog.example.com.—to represent the root. Browsers normally hide that dot.
The essentials
Registered name
The label a registrant obtains within a registry namespace.
example in example.com
Subdomain
A delegated or configured name beneath a domain the holder already controls.
blog.example.com
Hostname
A domain name used to identify a host or service in a network context.
mail.example.com
Read names from right to left
Each step narrows the namespace and moves responsibility closer to the domain holder.
Root
The top of the DNS tree, represented by an empty final label.
Top-level domain
A delegated namespace such as com, org or ke.
Registered level
The name registered according to that namespace's rules.
Subdomains and hosts
Names the domain holder can create beneath the registered domain.
Not every registration happens directly left of the TLD
Some registries organise public registrations under a fixed second-level namespace.
| Example | TLD | Registrable domain | Subdomain |
|---|---|---|---|
| www.example.com | .com | example.com | www |
| shop.example.co.uk | .uk | example.co.uk | shop |
| api.example.ke | .ke | example.ke | api |
| docs.project.dev | .dev | project.dev | docs |
Use domain terminology precisely
- Call .uk the TLD; co.uk is a namespace beneath it.
- Distinguish a registered domain from a subdomain created by its holder.
- Do not call the path after a slash part of the domain name.
- Treat www as a hostname convention, not a required part of every site.
- Remember that labels are compared case-insensitively in ordinary DNS use.
- Check registry rules to learn the actual registrable boundary for each TLD.
Common questions
Is www part of the domain name?
It is a label within the full domain name www.example.com, but it is normally a subdomain or hostname beneath the registered domain example.com.
What is a second-level domain?
It is the level immediately below a TLD. In example.com, example is second-level. In co.uk, co is also second-level, but public registrations commonly occur one level lower.
How many subdomain levels can I create?
DNS supports many labels, subject to per-label and full-name length limits. Operational clarity usually matters long before the technical limit.
Is the slash part of a domain?
No. In a web URL, the slash begins the path after the host. It identifies a resource or route within the site.
Keep learning
The next concepts to understand
Next step
Test the registrable part
Enter a complete idea and compare its status across available top-level domains.