Thought, idea (6)
I believe the answer is:
notion
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">thought</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(notion is a kind of thought)</span><br/ ><br/ >'<span class="explanation-format__original">idea</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(notion is a kind of idea)</span><br/ ><br/ ></span>
(Other definitions for notion that I've seen before include "Vague impression" , "Idea or fancy" , "A vague and possibly incorrect opinion" , "Caprice" , "Whimsical idea or small sewing article" .)