Rummikub piece (4)
I believe the answer is:
tile
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">rummikub 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 "Mah-jong piece" , "Ceramic rectangle" , "Flat, thin slab to cover surface" , "Roofing or flooring item" , "Small slab of baked clay for covering walls, roofs etc" .)