Yardstick, norm (8)
I believe the answer is:
standard
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">yardstick</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >'<span class="explanation-format__original">norm</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for standard that I've seen before include "Classic" , "Flag - level of attainment" , "Principle" , "Normal, average" , "Stock - basic - flag" .)