Employment in houses (3)
I believe the answer is:
use
'employment' is the definition.
('use' can be a synonym of 'employment')
'in houses' is the wordplay.
'in' indicates the answer is hidden within the clue.
'USE' is hidden in the letters of 'houses'.
(Other definitions for use that I've seen before include "Exploit; custom" , "Put to work" , "Employ, put into service" , "Application" , "Resort to - operation" .)