Time of therapy (3)
I believe the answer is:
era
'time' is the definition.
(era is a kind of time)
'of therapy' is the wordplay.
'of' indicates the answer is hidden within the clue.
'ERA' can be found hidden inside 'therapy'.
(Other definitions for era that I've seen before include "Important historical period" , "Important time" , "Geological age" , "Long period of time" , "quite some time" .)