Track official (5)
I believe the answer is:
timer
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">track official</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 timer that I've seen before include "Maybe watch" , "Watch, for example" , "Preset mechanisation to activate a device" , "It measures intervals" , "Preset activator" .)