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heyday

1 American  
[hey-dey] / ˈheɪˌdeɪ /
Or heydey

noun

  1. the stage or period of greatest vigor, strength, success, etc.; prime.

    the heyday of the vaudeville stars.

  2. Archaic. high spirits.

heyday 2 American  
[hey-dey] / ˈheɪ deɪ /

interjection

Archaic.

  1. (used as an exclamation of cheerfulness, surprise, wonder, etc.)

heyday British  
/ ˈheɪˌdeɪ /

noun

  1. the time of most power, popularity, vigour, etc; prime

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of heyday1

1580–90; variant of high day, apparently by confusion with heyday 2

Origin of heyday2

1520–30; rhyming compound based on hey; replacing heyda < German hei da hey there

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Years after their heyday, Seals & Crofts would be regarded as purveyors of what came to be known as yacht rock.

From Los Angeles Times • Mar. 26, 2026

During their 1960s heyday, conglomerates were even hotter and they took advantage by using their lofty stock prices to buy hundreds of often unrelated businesses.

From The Wall Street Journal • Mar. 17, 2026

On Saturday mornings in South Korea, you can tune in for a weekly dose of "Leeds Era Once Again", a TV show aimed at helping contestants rediscover their heyday.

From BBC • Mar. 13, 2026

Through much of its heyday, BuzzFeed saw its revenue grow every year, but it could never quite close the gap on losses that ran as high as $50 million annually.

From MarketWatch • Mar. 13, 2026

He is slender now, but during his heyday, Flom was extremely overweight.

From "Outliers" by Malcolm Gladwell

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.