It isn't without a reason that the internet is called the world wide web. It sure does cast a web, a vast one at that, throughout the length, breadth and width of the globe. Web development, if one has to explain in simple layman's language, is just that - developing a website. Sure, it does sound simple. But this is not just about developing a fuss-free single page with some text thrown about in neat columns.
Web development is not just for the internet. One can develop a website for the private network called the 'intranet' as well. Whether a single page of text or a more nuanced multiple page internet application or e-business, web development can involve an array of functions including but not limited to, web design, web engineering, web server configuration,writing markup, coding and e-commerce development.
Graphic designers and other related technicians work towards the aforesaid, as well as on the front-end, back-end and full-stack development. Front-end developers work with everything that the user engages with directly while back-end refers to the server side of the application. Full-stack developers take full stock of the front and back-ends of a website or application by working on both.
Web development can, in all probability, use content management systems too, referred to as CMS in short.