Undecennial

1 definition found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Undecennial \Un`de*cen"ni*al\, a. [See {Undecennary}, and cf.
     {Decennial}.]
     Occurring or observed every eleventh year; belonging to, or
     continuing, a period of eleven years; undecennary; as, an
     undecennial festival.
     [1913 Webster]