Etymology Late 16th century, from earlier heyda (1520s), as exclamation – compare hey, hei. Sense “period of success, vigor” is a respelling as heyday based on unrelated day (as “period of time”) – compare day in the sun.
1
A period of success, popularity, or power; prime.
The early twentieth century was the heyday of the steam locomotive.
Must your hot ytch and plurisie of lust, The heyday of your luxury, be fedd Up to a surfeite, and could none but I Be pickt out to be cloake to your close tricks, Your belly-sports?c. 1626 or 1629–1633 (first performance), [John Ford], ’Tis Pitty Shee’s a Whore […], London: […] Nicholas Okes for Richard Collins, […], published 1633, →OCLC, Act IV:
2 more examples
She started learning the craft at age 13 from her father, who founded the family's tile business, Kam Fat Mahjong, in 1962. Masters who would visit Hong Kong during its manufacturing heyday in the 1970s and 80s also shared their techniques and trained apprentices.2025 July 27, Kathleen Magramo, “The game is almost over for one of Hong Kong’s last mahjong carvers”, in CNN:
There has been a marked shift in viewing habits since the channels’ heyday, with music videos now more commonly consumed on YouTube and social media rather than television.2026 January 1, Max Pilley, “MTV shuts down final music-only channels with ‘Video Killed The Radio Star’”, in NME:
2
Archaic An exultation of the spirits; gaiety; frolic.
Etymology Late 16th century, from earlier heyda (1520s), as exclamation – compare hey, hei. Sense “period of success, vigor” is a respelling as heyday based on unrelated day (as “period of time”) – compare day in the sun.
1
A lively greeting.
"Heyday, Miss Morland!" said he. "What is the meaning of this? I thought you and I were to dance together."1798, Jane Austen, Northanger Abbey:
2
Obsolete An expression of frolic and exultation, and sometimes of wonder.
"Come follow me, my wags, and say, as I say. There's no riches but in rags; hey day, hey day, &c."1600, Ben Jonson - Cynthia's Revels
Bass. Heydey! good words, good words, I must beleeue'em And be a Coxcombe for my labor.1633, John Ford, The Broken Heart, act IV, scene i, page 252:
1 more example
Here Jones, having ordered a servant to show a room above stairs, was ascending, when the dishevelled fair, hastily following, was laid hold on by the master of the house, who cried, “Heyday, where is that beggar wench going? Stay below stairs, I desire you.”1749, Henry Fielding, The History of Tom Jones, a Foundling, volume (please specify |volume=I to VI), London: A[ndrew] Millar, […], →OCLC: