Parents occasionally sent back meal (3)
I believe the answer is:
tea
'meal' is the definition.
(tea is a kind of meal)
'parents occasionally sent back' is the wordplay.
'occasionally' means one should take alternating letters.
'sent back' says the letters should be written backwards.
The alternate letters of 'parents' are 'aet'.
'aet' backwards is 'TEA'.
(Other definitions for tea that I've seen before include "and 18 Across: Utensils for afternoon meal" , "Popular beverage brewed at home" , "Darjeeling, e.g." , "Brew" , "going to pot?" .)