Definition:

Server-side scripting is a web server technology in which a user’s request is verified by running a script directly on the web server to generate dynamic web pages. It is usually used to provide interactive web sites that interface to databases or other data stores. This is different fromclient-side scripting where scripts are run by the viewing web browser, usually in JavaScript. The primary advantage to server-side scripting is the ability to highly customize the response based on the user’s requirements, access rights, or queries into data stores.

Server-side scripting @ Wikipedia