Something that occurs once every 100 years is known as centennial.
Something that happens every 100 years is called a centennial. It marks a significant milestone or anniversary reaching the 100-year mark.
A century.
A 90 year old is called an nonagenarian. Nonagenarian are people who are over the age of 90 years old.
A year can be less than 365 days if it is a leap year, which has an extra day (February 29) added to keep the calendar year synchronized with the astronomical year. Leap years occur every four years, with the exception of years that are divisible by 100 but not by 400.
The name of the first person to reach what is now called the Philippines is lost to history because that person got there thousands of years ago, before writing was established in the area. The first Europeans to reach what is now called the Philippines were the crew of Ferdinand Magellan's expedition.
Jose Rizal's mother was called Injustice because she was wrongly accused of attempting to poison her brother-in-law. Despite evidence proving her innocence, she was still imprisoned for two and a half years before being acquitted. This unjust accusation deeply affected Rizal and his family.
Quadrenial
decennial Occurring every ten (10) years. Also tenth anniversary
A triennial event happens every three years.
Something that happens every three years is a triennialevent.
Something that happens once a century.
Something that happens every six years is sexennial.
Something that happens every 5 years
Quinquennial = something that happens every 5 years. Lustral = also something that happens every 5 years or we could invent: semi-Decennial: where semi is half and Deccennial happens every 10 years.
tercentennial
pentennial
Every 100 years is called a century, made up of 10 decades.
Biennial or biannual can refer to something which happens every two years.