Your "birthday" in English refers to the date on which you were born. It's the annual recurrence of that date, celebrated as an anniversary of your birth.
In simpler terms, a birthday is:
- The date of your birth: The specific day, month, and year you were born.
- An anniversary: A yearly celebration of your birthdate.
- A personal holiday: A day often marked with celebrations, gifts, and gatherings with loved ones.
So, if someone asks "What is your birthday?", they want to know the date you were born.