Alfresco meal (6)
I believe the answer is:
picnic
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">alfresco meal</span>' is the definition.<br/ ><span class="explanation-format__explanation">(an alfresco meal is eaten outside)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for picnic that I've seen before include "Outdoor repast" , "Informal meal outside" , "outdoor eating" , "external courses?" , "Meal eaten outside" .)