Old units of length (6)
I believe the answer is:
inches
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">old units of length</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for inches that I've seen before include "Slowly makes one's way" , "small amount" , "Edges slowly" , "Very small measures of length" , "Old units of length" .)