Rested one day of the week (3)
I believe the answer is:
sat
I believe this clue is a double definition.
'rested' is the first definition.
(I've seen this before)
'one day of the week' is the second definition.
(Sat is an example)
(Other definitions for sat that I've seen before include "Rested" , "part of the weekend" , "nearly half a day" , "Took (an exam)" , "Was in session" .)