Firstly, i would clarify about what a web host is all about.
Web host is a collection of files stored in a particular server. however, when you view a website from (www) this simply means you are receiving programming code written in different languages. example a website may have been written in php and python. wordpress is an example of website written with php.
When a browser receives a programming code used in a website, the code which your browser received was written in scripts and got transformed to features such as navigation, comment boxes, website margin & border.
WEB, HOST; SERVER: In this three words, i would explain the meaning of each i mentioned.
Web: A web is system of files, which supports collection of servers and documents in the internet sites. which is able to display such as images, audio, videos, animation through the process of html.
Host: This an internet hosting service provider, the are company which is resposible for your website server. however, a host server consist of tools which will enable you to create a website. example is the (CPANEL).
NOTE: Host is the house of your website while domain is the name of your website. Website host are incharge of bugs which may exist in your server which you purchased.
Server: Server is a computer programme, which is able to provide functionalities and managment to other computer softwares.
NOTE: every website is ruined on a server and your host is your website landlord, This because the host provided server to your service.
CMS: This stands for content management system and i know you will like to build a website without programming skills if it happens that you are not a programmer. their are many companies which has conclusion with content management system to run their own cms. example: WIX, WAPKA, WEEBLY every cms has its own structure and design, using a cms owned by a website builder company such as WEEBLY, WIX, WAPKA is self owned by the company. this simply means you cant see wordpress, Joomla, bbpress in them.
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some of the content management system softwares are free in their own company and website. the have free versions and most of them are limited to individual use. unlike the paid version which you purchased from a host company that support all features.
However, wordpress is the most popular cms known software with upto 18million installation on the other hand Joomla with 2.5million.
WordPress: wordpress is an open source content management system software, it is the most popular blogging tool and website creation software, it is a standalone Software and written with php.