Couple I encountered upon returning (4)
I believe the answer is:
item
'couple' is the definition.
(a romantic couple are 'an item')
'i encountered upon returning' is the wordplay.
'encountered' becomes 'met' ('meet' can be a synonym of 'encounter').
'upon returning' is a reversal indicator.
'met' in reverse letter order is 'tem'.
'i'+'tem'='ITEM'
(Other definitions for item that I've seen before include "story" , "Whole individual unit" , "Two people considered together (informal)" , "Bit of news to broadcast" , "Feature" .)