What is Domain?

The domain is Basically an Identification string. Domain foreword request to a very specific IP. That means when you browse to https://www.samim.com.bd BTCL domain service provider will foreword you to an IP address (data center)

URL: Uniform Resource Locator. 

https://www.samim.com.bd/public_html/home.html

HTTP

HTTP is a hypertext transfer protocol. It is an application transmitting hypermedia documents, such as HTML, CSS

HTTPS

Hypertext Transfer Protocol Secure (https) is a combination of the Hypertext Transfer Protocol (HTTP) with the Secure Socket Layer (SSL)/Transport Layer Security (TLS) protocol. TLS is an authentication and security protocol widely implemented in browsers and Web servers.

Subdomain: 

A subdomain is an additional part of your main domain name. Subdomains are created to organize and navigate different sections of your website. For www, it pointed to the IP address of hosting sources. 

Domain Name: computerhope

Domain Sufix: .com

A domain suffix is the last part of a domain name and is often referred to as a "top-level domain" or TLD. Popular domain suffixes include ".com," ". net," and ". org," but there are dozens of domain suffixes approved by ICANN.

the domain foreword visitor to IP of data center