I expect the boffins and certain schools of philosophy have definitions for the word 'relativism.' I don't. To me, it bespeaks of something or someone being relative to something else. For example, if I were suspended weightless inside a white-painted chamber with no discernable light source, where there were no corners, no shadows, nothing with which I could discern shape, and if that room were sound proofed, I would be relative to nothing outside of my physical body (discounting memory, bodily functions and the like) I would be HERE but there would be nothing or no thing there.
But put a dot on the wall and...! I am here. It is there. I am big, it is small. I am this, it is that. So I am relative now to something. And even at that stage the comparisons begin. Maybe that's what relativism is. Comparison.