server-side include(SSI) The facility provided by several {HTTP} {servers}, e.g. {NCSA httpd}, to replace certain {HTML} {tag}s in one {HTML} file with the contents of another file at the time when the file is sent out by the server, i.e. an {HTML} {macro}. {NCSA httpd tutorial (http://hoohoo.ncsa.uiuc.edu/docs/tutorials/includes.html)}. (1996-09-08)