birthday

noun

birth·​day ˈbərth-ˌdā 

1

a

: the day of a person's birth

b

: a day of origin

2

: an anniversary of a birth

her 21st birthday

Examples of birthday in a Sentence

Her birthday is September 30th.

Today is his 21st birthday.

The company just celebrated its 50th birthday.

Recent Examples on the Web

Many of the cards and other messages fill the walls at an indoor Punch birthday exhibit where visitors can also view video chronicling Punch from his earliest days. — ABC News, 25 July 2026

In our house growing up, the birthday tradition was that everyone got to request their favorite cake. — Cameron Beall, Southern Living, 25 July 2026

America just blew out the candles on its 250th birthday — a moment to celebrate the freedoms and ideals that define us. — Brendan Bechtel, Fortune, 25 July 2026

Two months later, Kelly posted photos of them in a birthday Instagram tribute for Reynolds. — Francesca Gariano, PEOPLE, 25 July 2026

Word History

First Known Use

14th century, in the meaning defined at sense 2

Phrases Containing birthday

• birthday suit

Rhymes for birthday

• airway
• allay
• archway
• array
• ashtray
• assez
• astray
• aue
• away
• ballet
• belay
• beltway

Kids Definition

birthday

noun

birth·​day ˈbərth-ˌdā 

1

: the day or anniversary of one's birth

2

: the day or anniversary of a beginning