[kstar]

Originally Posted by slodave

I wasn't born on the 29th, but grew up with someone who did. Not really a big deal. They just celebrated on the 28th the other years.

Your friend was a "leapling".

More from Wiki:

Birthdays

A person born on February 29 may be called a "leapling". In common years they usually celebrate their birthdays on 28 February or 1 March.

For legal purposes, their legal birthdays depend on how different laws count time intervals. In Taiwan, for example, the legal birthday of a leapling is 28 February in common years, so a Taiwanese leapling born on February 29, 1980 would have legally reached 18 years old on February 28, 1998.
“ If a period fixed by weeks, months, and years does not commence from the beginning of a week, month, or year, it ends with the ending of the day which proceeds the day of the last week, month, or year which corresponds to that on which it began to commence.　 But if there is no corresponding day in the last month, the period ends with the ending of the last day of the last month.[10] ”

In some situations, March 1 is used as the birthday in a non-leap year since it then is the day just after February 28.

There are many instances in children's literature where a person's claim to be only a quarter of their actual age turns out to be based on counting only their leap-year birthdays. A similar device is used in the plot of the Gilbert and Sullivan operetta The Pirates of Penzance.

Best,

Kurt