Definition: SSI stands for Server Side Include and means that you can include a file as part of your document while still on the server before it is executed and before the data reaches the client. One reason for doing this is that often data such as a header, footer, or variables are repeated in many places on the site. Using SSI allows these to each be stored in only one place, and thus only updated in one place when changes are made.
Also Known As: Server Side Include, Include, Require, PHP SSI
