D defs.my
Entry 2 senses · 2 variants Webster, 1913

Heyday

/hādā/ · Hey·day · IPA /ˈheɪdeɪ/
01 interj. An expression of frolic and exultation, and sometimes of wonder.
  1. 1.
    An expression of frolic and exultation, and sometimes of wonder.
02 n. The time of triumph and exultation; hence, joy, high spirits, frolicsomeness; wildness.
  1. 1.
    The time of triumph and exultation; hence, joy, high spirits, frolicsomeness; wildness.
    “The heyday in the blood is tame.” Shak.
    “In the heyday of their victories.” J. H. Newman.