birthday

UK: ˈbɜːθ.deɪ | US: ˈbɜːrθ.deɪ

Definition

  1. n. the annual anniversary of the day on which a person was born

  2. n. the day of a person's birth

  3. n. (figurative) the beginning or origin of something

Structure
birth <act of being born>day <24-hour period>
Etymology

The word "birthday" is a straightforward compound of "birth" (Old English gebyrd, meaning "the act of being born") and "day" (Old English dæg, meaning "a 24-hour period"). It emerged in Middle English (as birthdai) to denote the anniversary of one's birth. The concept of celebrating birthdays dates back to ancient cultures, but the term itself reflects the Germanic practice of combining concrete nouns to form new meanings.

Examples

  1. She baked a cake for her sister's birthday.

  2. His birthday falls on a weekend this year.

  3. The company celebrated its 10th birthday with a grand party.

  4. We surprised him with gifts on his birthday.

  5. The invention marked the birthday of modern technology.