A little girl celebrating her birthday.
Your birthday is defined as the day on which you are born, or the annual anniversary of that day.
If you were born on July 1, then July 1 is an example of your birthday.
- the day of a person's birth or a thing's beginning
- the anniversary of this day
in one's birthday suit
Informal naked; nude: a humorous usage
- The day of one's birth.
- The anniversary of one's birth.