Keeping time – from a second to a millennium – is an essential ingredient in our lives and the way we measure them.
We have special words for describing these moments in time. Since a new millennium
began not too many years ago, we are all familiar with that term, as we are with centuries (with centennial
or centenary
as adjectives), and perennial
– something which occurs annually. Here are a few that we don’t use as often:
Biennial
– occurring every two years (as opposed to biannual
, which is twice per year) Decennial
– occurring once a decade (also denary
is used at times). Vicennial
– occurring every twenty years Quadranscentennial
– a 25th anniversary year Triennial
– occurring every thirty years Quadrennial
– occurring every forty years Quintennial –
occurring every fifty years (in ancient times, it was called a jubilee year
). Sesquicentennial –
occurring every one hundred and fifty years Dodransbicentennial – occurring every 175 years Bicentennial – a two hundredth anniversary Sestercentennial – every 250 years or a quarter of a millennium
(also semiquintennial
can be used) Tercentennial – every 300 years (also called tricentennial at times) Quadricentennial – every 400 years Quincentennial – every 500 years, or a half of a millennium Sexacentennial – every 600 years Septuacentennial – every 700 years Octocentennial – an 800thanniversary year Nonagintennial – a 900thanniversary year Sesquimillennial – occurring every 1500 years Bimillennial – every 2000 years Trimillennial – every 3000 years Decamillennial – occurring every 10,000 years
We could keep going into the billions and trillions, but usually don’t need to use those terms. We never know, though, when we might need to use the above milestones. On July 4, 2026, we will celebrate the sestercentennial
year of the birth of the United States. In 2013, Gettysburg celebrated its sesquicentennial
year of the battle here. In 2022, this magazine will complete its quadranscentennial
year of publication. On February 22, 2032 – just a decade away – we will pass the tercentennial
anniversary of the birth of our first U.S. President, George Washington.
We have perfect words for milestone years – it’s a good thing to know them.