Son with father in resort (3)
I believe the answer is:
spa
'resort' is the definition.
(spa is a kind of resort)
'son with father' is the wordplay.
'son' becomes 's' (genealogical abbreviation for son).
'with' says to put letters next to each other.
'father' becomes 'pa' (pa can mean dad or father).
's'+'pa'='SPA'
'in' is the link.
(Other definitions for spa that I've seen before include "eg Vichy" , "Heated bath" , "Health and beauty treatment establishment" , "Hydromassage facility" , "A therapeutic hot spring" .)