Three-dimensional shapes (6)
I believe the answer is:
solids
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">three-dimensional shapes</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 solids that I've seen before include "Bodies or shapes with three dimensions" , "Food, as opposed to drinks" , "Three-dimensional shapes" , "Three-dimensional objects" , "They're not hollow" .)