noun
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an anniversary of the day of one's birth
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( as modifier )
birthday present
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the day on which a person was born
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any anniversary
Other Word Forms
Noun Inflected Forms
Etymology
Origin of birthday
Middle English word dating back to 1350–1400; see origin at birth, day
Explanation
Your birthday is the day of your birth! It’s the yearly anniversary that marks the day you were born. Not everyone celebrates, but a birthday is a good excuse for a party and cake. You can use birthday both to refer to the specific day of a baby's birth, and the annual marking of that day throughout the years that follow. Sometimes people talk about the birthday of a country, group, or even a building: "It's the art museum's fiftieth birthday next year." The Old English byrddæg originally referred to the celebration of a king or saint's birth, but over the years it was extended to include everyone.
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.
Rugby league star Kevin Sinfield is knighted while children's authors Malorie Blackman and Julia Donaldson are made dames in the King's Birthday Honours.
From BBC • Jun. 12, 2026
“Happy Birthday — and may every day be another wonderful secret,” the letter said.
From The Wall Street Journal • May 28, 2026
And there they were, a dozen or two members of that marching band, in full regalia, with two people holding a “Happy Birthday Eva!” banner and the rest blasting out the familiar tune.
From Los Angeles Times • Mar. 6, 2026
Presidents Day isn’t even officially called Presidents Day: It is designated by U.S. law as Washington’s Birthday and was created in 1885 to honor President George Washington.
From Barron's • Feb. 16, 2026
Some Birthday vs. a Particular Birthday Sigmund Freud once remarked that there was no such thing as a coincidence.
From "Innumeracy: Mathematical Illiteracy and Its Consequences" by John Allen Paulos
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.
