'Centennially' definitions:
Definition of 'centennially'
From: WordNet
adverb
Every hundred years; once in a century; "the birthday of this city is being celebrated centennially"
Definition of 'Centennially'
From: GCIDE
- Centennially \Cen*ten"ni*al*ly\, adv. Once in a hundred years. [1913 Webster]