heyday
hay day
- n the period of greatest prosperity or productivity
 
- In its heyday this studio was a beehive of activity and cars and stars flitted in and out like bees in a beehive.
 - During their heydays, the Beatles were like a cultural road roller, flattening old beliefs in their wake.
 - Today she is only a shadow of what she was in her heyday. It was difficult to get an appointment with her during that time.