Concentrate (5)
I believe the answer is:
focus
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">concentrate</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for focus that I've seen before include "Point of convergence of light, etc" , "Centre of interest or activity (5)" , "Central point" , "Concentrate, zero in" , "Concentration of attention or energy" .)