What Is a Subdomain?
A subdomain is a distinct section of a website that sits in front of the main domain name — blog.example.com or shop.example.com are both subdomains of example.com.
How It Works
Subdomains function almost like separate sites in terms of how they’re structured and, in some cases, hosted, while still living under the same overarching domain and often sharing branding with the main site.
Subdomain vs Subfolder for SEO
A subfolder (example.com/blog/) keeps content clearly under the main domain’s existing authority. A subdomain has historically been treated with more ambiguity — some evidence suggests Google can evaluate subdomains largely as part of the same overall site, while other cases show authority not transferring as cleanly as it does with subfolders. Where there’s no strong technical reason to separate content onto a subdomain (different platform, different team), a subfolder is generally the safer default for consolidating SEO value.
