A URL,  informally termed a web addressalso known as Uniform Resource Locator is a reference to a web resource that specifies its location on a computer network and a mechanism for retrieving it. URLs are most commonly used to reference web pages (http). Hypertext Transfer Protocol.

A URL in the form, has several parts & they are explained below.

top-level domain in the domain name, the top-level domain is “com“. Also known as domain name extension (ie, .com is the extension) also known as suffix.

A sub-domain is a domain that is part of a larger domain name in DNS hierarchy. DNS hierarchy consists of the root-level domain at the top, underneath which are the top-level domains, followed by second-level domains and finally subdomains.

sub-domains. For example, in the domain name, “webopedia” is a sub-domain of the larger second-level domain “internet”. A second-level domain (SLD) is the portion of the domain name that is located immediately to the left of the dot.

From Hostgator – see this link for 1:35 video (optional)

It is not always necessary to register a new domain name when the one you already own will work perfectly fine. Rather than registering a new domain name, you can always create a subdomain using a domain you already own.

A subdomain is a second website, with its own unique content, but there is no new domain name. Instead, you use an existing domain name and change the www to another name. The subdomain name looks like, (assuming you already host or own

Domain names are used in URLs to identify particular Web pages. For example, in the URL, the domain name is While index.html is a particular page (or html file) in the website.


Related image

Image result for subdomain example

Image result for second-level domains

Image result for second-level domains

For diagram above, the bottom level or third level domain for, sales would be a sub-domain of

Root domain would be The child domains below are also considered sub-domains.

Image result for root domain

Image result for root domain


Also, see another post for more on sub-domains.

About martello44

student of all things Web
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