Aeons (4)
I believe the answer is:
ages
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">aeons</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 ages that I've seen before include "Aeons" , "... of Man, according to WB Yeats" , "Gets older" , "A long time (colloq.)" , "Long periods" .)