The compiling of dictionaries (12)
I believe the answer is:
lexicography
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">the compiling of dictionaries</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 lexicography that I've seen before include "Process of dictionary compilation" , "The compilation of dictionaries" , "Dictionary compiling" , "Dictionary creation" , "The compiling of dictionaries" .)