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birthday

American  
[burth-dey] / ˈbɜrθˌdeɪ /

noun

  1. the anniversary of a birth.

  2. the day of a person's birth.

  3. a day marking or commemorating the origin, founding, or beginning of something.

  4. the festivities or celebration marking such a day or anniversary.

birthday British  
/ ˈbɜːθˌdeɪ /

noun

    1. an anniversary of the day of one's birth

    2. ( as modifier )

      birthday present

  2. the day on which a person was born

  3. any anniversary

"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 birthday

Middle English word dating back to 1350–1400; birth, day

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.

Many of them were asleep after celebrating till midnight at a birthday party.

From The Wall Street Journal

They describe the details of their lives; practising yoga despite the sounds of explosions, eating birthday cake alone and venturing out to near-empty coffee shops.

From BBC

He was generally feeling unwell but had no bowel symptoms, yet needed surgery just two days after his 50th birthday.

From BBC

Just before her fourth birthday Sophia Scott's parents were told she had a condition that causes childhood dementia.

From BBC

And this year he will have a commemorative coin bearing his image, minted to mark America's 250th birthday.

From Barron's

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.