x or y, on a graph (4)
I believe the answer is:
axis
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">x or y on a graph</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for axis that I've seen before include "x or y line on a graph" , "Spindle - German/Italian alliance - deer" , "Fixed reference line" , "all revolves around this" , "Feasible" .)