Husband and son sit around university (6)
I believe the answer is:
spouse
'husband' is the definition.
(a husband is a male spouse)
'son sit around university' is the wordplay.
'son' becomes 's' (genealogical abbreviation for son).
'sit' becomes 'pose' (as in sitting for a painter).
'around' means one lot of letters goes inside another.
'university' becomes 'U' (abbreviation for university).
'pose' enclosing 'u' is 'pouse'.
's'+'pouse'='SPOUSE'
'and' acts as a link.
(Other definitions for spouse that I've seen before include "Possibly wife" , "old lady?" , "Husband or wife" , "Partner in marriage" , "Consort" .)