a cell or range reference in a formula whose location is interpreted by Excel in relation to the position of the cell that contains the formula
URL of a form which expresses the link to a page or other data as an item existing in some other location in relation to the current document. For example, a URL of the form a href="second.dir/myfile.html" points to a location in the "second.dir" directory (which is in the same directory as my current page) which then points to the myfile.html page. Notice that there is no initial slash (/) before the "second.dir" directory. An Absolute Reference might look like a href="/mydir/second.dir/myfile.html".
Using normal cell reference form (like C3) is a relative reference. When the cell contents is moved, any formulas that refer to that cell are changed to use the new location.