Act of Parliament (7)
I believe the answer is:
statute
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">act of parliament</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 statute that I've seen before include "Act of law" , "Set taut (anag.)" , "Law, rule" , "Act of Parliament" , "Written law" .)