Counting-frame (6)
I believe the answer is:
abacus
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">counting-frame</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for abacus that I've seen before include "Old calculator" , "Counting machine" , "Calculating frame" , "Beaded counting frame" , "frame of sorts" .)