Days of old (4)
I believe the answer is:
yore
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">days of old</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 yore that I've seen before include "Formerly, of long ago" , "Old usage for formerly, as in days of. . ." , "Bygone time" , "Long ago (poetic)" , "Long ago (literary)" .)