Definition of Relative URL:
Partial internet address which points to a directory or file in relation to the current directory or file. When creating a link in a websites code, if just a filename is given without any other modifications, that is an indicator to find that file within the current directory and link to it. Modifiers can be added to a relative URL which indicate that the file is found in a higher directory, or code can be added to indicate that the file is in a deeper directory. Relative URLs are often easier to maintain than absolute URLs.
Meaning of Relative URL & Relative URL Definition