adjective Etymology: Late Latin septennium period of seven years, from Latin septem + -ennium (as in biennium) Date: 1640 occurring or being done every seven years, consisting of or lasting for seven years, ~ly adverb
SEPTENNIAL
Meaning of SEPTENNIAL in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012