<P> A decade is a period of ten years . The word is derived ( via French and Latin ) from the Ancient Greek : δεκάς ( / ðɛkˈɑːs / , transliteration = dekas ) , which means a group of ten . Other words for spans of years also come from Latin : biennium ( 2 years ) , triennium ( 3 years ) , quadrennium ( 4 years ) , lustrum ( 5 years ) , century ( 100 years ) , millennium ( 1000 years ) . </P>
<P> A decade is a period of ten years . The word is derived ( via French and Latin ) from the Ancient Greek : δεκάς ( / ðɛkˈɑːs / , transliteration = dekas ) , which means a group of ten . Other words for spans of years also come from Latin : biennium ( 2 years ) , triennium ( 3 years ) , quadrennium ( 4 years ) , lustrum ( 5 years ) , century ( 100 years ) , millennium ( 1000 years ) . </P>
what is a period of 3 years called
what is a period of 3 years called
triennium
triennium