Subdomain
A prefix added to a domain name to create a separate section of a website.
A subdomain is an additional part of your main domain that can host separate content or services. It appears before your main domain name.
Subdomain Structure:
[subdomain].[domain].[tld]
blog.example.com
shop.example.com
app.example.com
Common Subdomain Uses:
- blog.: Separate blog platform
- shop.: E-commerce store
- app.: Web application
- support.: Help desk
- staging.: Development testing
- api.: API endpoints
- mail.: Webmail access
Subdomains vs Subdirectories:
| Subdomain | Subdirectory |
|---|---|
| blog.example.com | example.com/blog |
| Separate DNS needed | Same hosting |
| Can point elsewhere | Must be on same server |
| Seen as different site | Seen as same site |
Creating Subdomains:
- Add DNS record (A or CNAME) for the subdomain
- Configure your web server to respond to it
- Set up content/application at that location
SEO Consideration: Search engines often treat subdomains as separate sites. For blog SEO benefit, many prefer subdirectories (example.com/blog) over subdomains (blog.example.com).
Why It Matters
Subdomains let you organize different sections of your online presence, use different hosting platforms, and create clear separation between services—all under one main domain.
Practical Example
Your main site is at example.com. You add shop.example.com pointing to Shopify for e-commerce, and blog.example.com pointing to Ghost for your blog. All use your main domain's credibility.
Related Terms
A Record
TechnicalA DNS record that maps a domain name to an IPv4 address.
CNAME Record
TechnicalA DNS record that creates an alias from one domain to another.
DNS (Domain Name System)
TechnicalThe system that translates domain names into IP addresses.
Domain Name
BasicsA human-readable address used to access websites on the internet.
Explore More Terms
Browse our complete glossary of domain name terminology.