Numerical comparison (5)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">numerical comparison</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 ratio that I've seen before include "2:1, for example" , "Relationship found in a riot" , "Mathematical relationship" , "E.g. two to one" , "Proporation, quantitative relation" .)