To understand Subdomain, first, you have to understand what a domain is. The domain is the name of your website, like WWW.MARKETINGWEBTECHNO.COM This is the name of our website. It is the main address or web address of your site, and the domain is running from the system. It is called DNS. For more information about the domain,  you can read this post -  What is Domain Name? Therefore, An entire domain name is divided into three parts -  Top-level domains i.e., TLD Second level domains ie, SLDAll domain ( Subdomain ) For example, we take www.marketingwebtechno.com -  Also, Here it is.COM, which is the top-level domain (TLD) of this domain name, which we have mentioned in the post and the  MARKETINGWEBTECHNO.COM, it is the second-level