Former name of Iran (6)
I believe the answer is:
persia
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">former name of iran</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 persia that I've seen before include "Iran, formerly" , "Old land" , "It's now known as Iran" , "Former name of Iran" , "Old name for country at 25 Across" .)