Subdomain

A subdomain is a prefix added to a root domain that creates a separate section of a website, treated by servers and potentially by search engines as a distinct entity — for example, "blog.example.com" or "shop.example.com." Google has stated it treats subdomains and subdirectories similarly, but in practice, subdomains may have independent authority and crawl budgets.

Subdomain performance is tracked separately in Google Search Console by adding each subdomain as its own property, and in Ahrefs and SEMrush via domain filtering. Technical SEOs analyze whether subdomain vs. subfolder structures serve their specific use case based on content independence requirements and authority consolidation goals.