A parallelogram with four right angles (9)
I believe the answer is:
rectangle
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">a parallelogram with four right angles</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for rectangle that I've seen before include "Figure on plane" , "regular sort of figure" , "Shape of football pitch" , "Parallelogram with four right angles" , "Four sides involved in this" .)