a persons birthday on the day of a leap year
Biannual
its tyler m
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.
A synonym for every five years is quinquennial: as an adjective describes something that happens every five years or that lasts for five years; the noun means the fifth anniversary or a period of five years.
Every 4 years
The letter "m" :DOnce in a minute, twice in a moment, and never in a thousand years.
An event that occurs once every three years.
"Decentennial" is not a recognized English word. It may be a misspelling or a made-up term. If you meant "decennial," it refers to something that occurs once every ten years.
Something that is octennial occurs every eight years. Octennial can also mean something having to do with eight years. Oct means eight (like octopus, octogon) and enial means years (centenial, perenial)
every two years
4 years 4 yearsThe Summer Olympics are held once every 4 years.