a link inside of an HTML document that refers to another file by the shortest possible reference. If the file is in the same directory, then only the file name is specified. If the file is one directory below, then it is specified in the form "directory/file.html". If it is one directory above, then the parent directory marker is used: "../file.html"
A relative link is a hyperlink that does not include an entire domain name, folder or subdirectory name and file name together in the URL. A link that is defined by its relative position to the current URL. For example: optimizationbasics.html