Gear tooth (3)
I believe the answer is:
cog
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">gear tooth</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 cog that I've seen before include "Tooth on the rim of gear wheel" , "Each of series of teeth on wheel" , "Little gearwheel" , "bar" , "One on a gearwheel" .)