Tessellation piece (4)
I believe the answer is:
tile
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">tessellation piece</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for tile that I've seen before include "Roof slabs" , "Flat, thin slab to cover surface" , "Thin slab of fired clay" , "Scrabble piece" , "Thin rectangular slab to cover surfaces" .)