Memorialise (6)
I believe the answer is:
record
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">memorialise</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for record that I've seen before include "Best ever - account" , "State officially; disc" , "Log - so far unsurpassed" , "Set down in writing" , "Highest achievement" .)