( a. )
Occurring or observed every eleventh year; belonging to, or continuing, a period of eleven years; undecennary; as, an undecennial festival.
( a. )
Occurring or observed every eleventh year; belonging to, or continuing, a period of eleven years; undecennary; as, an undecennial festival.
Webster's Revised Unabridged English Dictionary. Пересмотренный полный словарь английского языка Webster. 2012