Brain section (4)
I believe the answer is:
lobe
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">brain section</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 lobe that I've seen before include "Base of ear" , "Leaf division" , "Roundish projecting part" , "part of brain" , "Lower part of the ear" .)