The process of moving code from a testing server to a public host (web server) is called Deployment. It is basically putting out your project to the world so that people can use it.
Once your site has been completed, tested and approved it will be deployed. Deployment day is a happy day. After days, weeks and possibly months, the completed website will be live for anyone using the internet and world wide web can view your site from anywhere in the world.
Within a few hours of going live, your site will propagate to web servers all over the planet which ensures that whoever may be viewing your site can have fast page load times. If the site were only on one web server, users from far away would be waiting for pages to load.