Measured against something else rather than absolutely. A relative claim is meaningless until its reference is named.
Latin relativus (having reference to), from relatus, past participle of referre (to carry back): re- (back) + ferre (to carry); a relative claim only carries meaning back to whatever it is measured against.
Measured against something else rather than absolutely. The root's carrying-back is not optional here — a relative claim means nothing until its reference is named.