Restaurant starter, informally
I believe the answer is:
app
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">restaurant starter informally</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for app that I've seen before include "Software program for a mobile device" , "bit of software" , "Program for a smart phone, in short" , "Software item" , "Software for mobile devices, in short" .)