A head of "Time" (4)
I believe the answer is:
luce
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">a head of time</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for luce that I've seen before include "Pike" , "Fish" .)