Returning loved ones cross the threshold (8)
I believe the answer is:
doorstep
'the threshold' is the definition.
('doorstep' can be a synonym of 'threshold')
'returning loved ones cross' is the wordplay.
'returning' is a reversal indicator.
'loved ones' becomes 'pets' (I can't explain this - if you can you should believe this answer much more).
'cross' becomes 'rood' (term for a crucifix).
'pets'+'rood'='petsrood'
'petsrood' back-to-front is 'DOORSTEP'.
Can you help me to learn more?
(Other definitions for doorstep that I've seen before include "Large slice of bread?" , "chunk of bread" , "sliced bread" , "Old song: ` `Oh Mother Kelly's ........' '" , "Thick slice of bread (informal)" .)