Ruler unit
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">ruler unit</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for inch that I've seen before include "Small measurement unit of distance" , "Creep, edge" , "Advance slowly" , "2.45 cm" , "One of a 2 down in a foot" .)