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

Having been signed in January, and impressed in pre-season, complications with his registration meant he was set to be blocked from featuring in competitive games until his 18th birthday in January 2027. — Cerys Jones, New York Times, 16 Aug. 2026

My local adult beverage store once sent me a birthday card with a discount on my favorite brew! — Chip Bell, Forbes.com, 15 Aug. 2026

Academy Award winner Halle Berry celebrated her 60th birthday by posting a series of sexy photographs online. — Brian Niemietz, New York Daily News, 15 Aug. 2026

So much so that updates about them often came in the form of birthday tributes from both Coigney and Mark. — Giovana Gelhoren, InStyle, 15 Aug. 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