___ Lovelace, Byron's daughter (3)
I believe the answer is:
ada
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">lovelace</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(computing pioneer Ada Lovelace)</span><br/ ><br/ >'<span class="explanation-format__original">byron's daughter</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ ></span>
(Other definitions for ada that I've seen before include "Girl's name, one letter short of a man's name" , "Palindromic girl's name" , "Computer lang.; f. name" , "Woman" , "-- Lovelace, pioneer in computing" .)