Emerge from an egg (5)
I believe the answer is:
hatch
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">emerge from an egg</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 hatch that I've seen before include "contrive to > emerge in > shade" , "Think up" , "Cook up" , "Mountain goat" , "Brood" .)