| BIENNIALS | • biennials n. Plural of biennial. • BIENNIAL n. something e.g. a plant occurring every two years; lasting for two years. |
| BRITANNIA | • Britannia prop.n. A female personification of Britain or the United Kingdom. • Britannia prop.n. (Historical) A province of the Roman Empire covering most of the island of Britain. • Britannia prop.n. A settlement in Newfoundland and Labrador. |
| DECENNIAL | • decennial n. The tenth anniversary of an event or happening. • decennial adj. Occurring every ten years. • decennial adj. Of or related to a ten-year period, as a term of office. |
| MILLENNIA | • millennia n. Plural of millennium. • MILLENNIUM n. (Latin) a period of one thousand years. |
| NOVENNIAL | • novennial adj. Of or relating to a 9-year period. • NOVENNIAL adj. recurring every ninth year. |
| OCTENNIAL | • octennial adj. Occurring every eight years. • octennial adj. Lasting or taking eight years. • OCTENNIAL adj. recurring every eighth year. |
| PERENNIAL | • perennial adj. Lasting or remaining active throughout the year, or all the time. • perennial adj. (Figuratively). • perennial adj. (Botany) Of a plant: active throughout the year, or having a life cycle of more than two growing seasons. |
| SEPTENNIA | • septennia n. Plural of septennium. • SEPTENNIUM n. a period of seven years. |
| SEXENNIAL | • sexennial adj. Pertaining to a period of six years; taking place once every six years. • sexennial n. A sexennial event. • SEXENNIAL adj. lasting six years, or happening once in six years. |
| TRIENNIAL | • triennial adj. Happening every three years. • triennial adj. Lasting for three years. • triennial n. A third anniversary. |
| VICENNIAL | • vicennial adj. Occurring once every twenty years. • vicennial adj. Lasting for twenty years. • VICENNIAL adj. occurring every twenty years. |