Dish as ordered by boy (5)
I believe the answer is:
salad
'dish' is the definition.
(type of meal or dish)
'as ordered by boy' is the wordplay.
'ordered' is an anagram indicator.
'by' means one lot of letters go next to another.
'boy' becomes 'lad' (informal term for boy).
'as' with letters rearranged gives 'sa'.
'sa'+'lad'='SALAD'
(Other definitions for salad that I've seen before include "one gets dressed" , "Raw vegetables, etc" , "Lettuce, cucumber etc" , "Food dish" , "Raw greens, mainly" .)