Cavities (5)
I believe the answer is:
holes
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">cavities</span>' is the definition.<br/ ><span class="explanation-format__explanation">(hole is a kind of cavity)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for holes that I've seen before include "Scrapes" , "Cavities" , "Empty spaces" , "Openings" , "Apertures" .)