Microscope component (4)
I believe the answer is:
lens
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">microscope component</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for lens that I've seen before include "Piece of glass, usually curved" , "town in France" , "optical equipment" , "Focusing glass" , "Part of the inner eye, or camera" .)