| OCTENNIAL | • octennial adj. Occurring every eight years. • octennial adj. Lasting or taking eight years. • OCTENNIAL adj. recurring every eighth year. |
| SEPTENNIA | • septennia n. Plural of septennium. • SEPTENNIUM n. a period of seven years. |
| CENTENNIAL | • centennial adj. Relating to, or associated with, the commemoration of an event that happened a hundred years before. • centennial adj. Happening once in a hundred years. • centennial adj. Lasting or aged a hundred years. |
| SEPTENNIAL | • septennial adj. Of or relating to a 7 year period. • SEPTENNIAL adj. lasting or continuing seven years; as, septennial parliaments. |
| CENTENNIALS | • centennials n. Plural of centennial. • CENTENNIAL n. a hundredth anniversary. |
| OCTENNIALLY | • octennially adv. Every eight years. • OCTENNIAL adv. recurring every eighth year. |
| BICENTENNIAL | • bicentennial adj. Relating to the 200th anniversary of an event or happening. • bicentennial adj. Occurring every two hundred (200) years. • bicentennial n. The 200th anniversary of an event or happening. |
| CENTENNIALLY | • centennially adv. As part of a centennial. • centennially adv. Once a century, every one hundred years. • CENTENNIAL adv. recurring every hundred years; lasting a hundred years. |
| SEPTENNIALLY | • septennially adv. Once in every seven years. • SEPTENNIAL adv. lasting or continuing seven years; as, septennial parliaments. |
| BICENTENNIALS | • bicentennials n. Plural of bicentennial. • BICENTENNIAL n. a two hundred year anniversary, also BICENTENARY. |
| TERCENTENNIAL | • tercentennial n. The three-hundredth anniversary of an event; tricentennial. • TERCENTENNIAL n. a three hundred year anniversary. |
| TRICENTENNIAL | • tricentennial n. The 300th anniversary of an event or happening. • tricentennial adj. Occurring every three hundred (300) years. • TRICENTENNIAL n. a three-hundred year anniversary. |
| QUINCENTENNIAL | • quincentennial adj. Of or related to a 500th anniversary. • quincentennial n. A 500th anniversary. • QUINCENTENNIAL n. a five hundred year anniversary. |
| SEMICENTENNIAL | • semicentennial adj. Of or related to a 50th anniversary, occurring every 50 years. • semicentennial n. A 50th anniversary. • SEMICENTENNIAL n. a 50th anniversary or its celebration. |
| TERCENTENNIALS | • tercentennials n. Plural of tercentennial. • TERCENTENNIAL n. a three hundred year anniversary. |
| TRICENTENNIALS | • tricentennials n. Plural of tricentennial. • TRICENTENNIAL n. a three-hundred year anniversary. |
| QUINCENTENNIALS | • quincentennials n. Plural of quincentennial. • QUINCENTENNIAL n. a five hundred year anniversary. |
| SEMICENTENNIALS | • semicentennials n. Plural of semicentennial. • SEMICENTENNIAL n. a 50th anniversary or its celebration. |