Happy Birthday

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).

There is a distinction between birthday and birthdate: The former, other than February 29, occurs each year (e.g. May 11), while the latter is the exact date a person was born (e.g., May 11, 1998).

In most legal systems, one becomes designated as an adult on a particular birthday (usually between 12 and 21), and reaching age-specific milestones confers particular rights and responsibilities. At certain ages, one may become eligible to leave full-time education, become subject to military conscription or to enlist in the military, to consent to sexual intercourse, to marry, to marry without parental consent, to vote, to run for elected office, to legally purchase (or consume) alcohol and tobacco products, to purchase lottery tickets, or to obtain a driver's licence. The age of majority is the age when minors cease to legally be considered children and assume control over their persons, actions, and decisions, thereby terminating the legal control and legal responsibilities of their parents or guardians over and for them. Most countries set the age of majority between 18 and 21.

Some notables, particularly monarchs, have an official birthday on a fixed day of the year, which may not necessarily match the day of their birth, but on which celebrations are held. Examples are:

Jesus Christ's traditional birthday is celebrated as Christmas Eve or Christmas Day around the world, on December 24 or 25, respectively. As some Eastern churches use the Julian calendar, December 25 will fall on January 7 in the Gregorian calendar. These dates are traditional and have no connection with the actual birthday date of Jesus, which was an unknown date, likely around September or possibly early October.
Similarly, the birthdays of the Virgin Mary and John the Baptist are liturgically celebrated on September 8 and June 24, especially in the Roman Catholic and Eastern Orthodox traditions (although for those Eastern Orthodox churches using the Julian calendar the corresponding Gregorian dates are September 21 and July 7 respectively). As with Christmas, the dates of these celebrations are traditional and probably have no connection with the actual birthdays of these individuals (and if Jesus was born in September or October, it would seem likely that John the Baptist, who was traditionally regarded to be six months older, was born around March or April).
The Queen's Official Birthday in Australia, Fiji, Canada, New Zealand, and the United Kingdom.
The Grand Duke's Official Birthday in Luxembourg is typically celebrated on June 23. This is different from the monarch's actual date of birth, which is on April 16.
Koninginnedag in the Kingdom of the Netherlands was typically celebrated on April 30. Queen Beatrix fixed it at the birthday of her mother, the previous queen, to avoid the winter weather associated with her own birthday in January. The present monarch's birthday is 27 April, and is also celebrated on that day and has replaced the 30th of April celebration of Koninginnedag.
The current Japanese Emperor Akihito's official birthday is December 23, which is a national holiday in Japan, whereas his actual date of birth is on November 12.
The previous Japanese Emperor Showa (Hirohito)'s birthday was April 29. After his death, the holiday was kept as "Showa no Hi", or "Showa Day". This holiday falls close to Golden Week, the week in late April and early May.
Kim Il-sung and Kim Jong-Il's birthdays are celebrated in North Korea as a national holiday.
Washington's Birthday, commonly referred to as Presidents' Day, is a federal holiday in the United States that celebrates the birthday of George Washington. President Washington's birthday is observed on the third Monday of February each year. However, his actual birth date was either February 11 (Old Style), or February 22 (New Style).
In India, every year October 2 which marks the Birthday of Mahatma Gandhi, is declared as a holiday. All the liquor shops are closed across the country in honour of Gandhi not consuming liquor.
Martin Luther King, Jr. Day is a federal holiday in the United States marking the birthday of Martin Luther King, Jr. It is observed on the third Monday of January each year, which is around the time of King's birthday, January 15.
Mawlid is the official birthday of Muhammad and is celebrated on the 12th or 17th day of Rabi' al-awwal by adherents of Sunni and Shia Islam respectively. These are the two most commonly accepted dates of birth of Muhammad.