Hey"day` (?), interj. [Cf. G. heida, or hei da, D. hei daar. Cf. Hey, and There.]
An expression of frolic and exultation, and sometimes of wonder.
B. Jonson.
© Webster 1913.
Hey"day` (?), n. [Prob. for. high day. See High, and Day.]
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.
© Webster 1913.