Mother and child meeting builder (5)
I believe the answer is:
mason
'builder' is the definition.
(I know that mason is a type of builder)
'mother and child' is the wordplay.
'mother' becomes 'ma' (ma can mean mother).
'and' means one lot of letters go next to another.
'child' becomes 'son' (male child).
'ma'+'son'='MASON'
'meeting' is the link.
(Other definitions for mason that I've seen before include "one in construction" , "secretive lodger!" , "Dresser" , "One going to work in building" , "Construction industry employee" .)