Happy Birthday Song

A birthday is an occasion when a person or institution celebrates

A birthday is an occasion when a person or institution celebrates the anniversary of their birth. Birthdays are celebrated in numerous cultures, often with a gift, party, or rite of passage.

Many religions celebrate the birth of their founders with special holidays (e.g. Christmas, Buddha's Birthday).

Note the distinction between birthday and birthdate: The former occurs each year (e.g. December 18), while the latter is the exact date a person was born (e.g., December 18, 1998).