Part of working week The Times had shortened (3)
I believe the answer is:
wed
I believe this is a double definition.
'part of working week' is the first definition.
(short for Wednesday)
'the times had shortened' is the second definition.
(contraction of 'we had' - this is a Times puzz;e)
(Other definitions for wed that I've seen before include "Unite closely" , "Took in marriage" , "Married" , "Espouse" , "Marry" .)