Octennial - definition of octennial by The Free Dictionary
1. occurring every eight years
2. lasting for eight years
[C17: from Latin octennium eight years, from octo eight + annus year]
References in classic literature
Of late these shackles, if I mistake not, have been broken; and octennial
parliaments have besides been established.
MOBO-BACO, trained by Ron Hodges and ridden by Steve Drowne, took advantage of a wayward display by Octennial
- who hung badly - to take the seven-furlong seller.