1. 
   Novennial
   No·ven'ni·al adjective [ Latin novennis of nine years; novem nine + annus year.] Done or recurring every ninth year.
   Found op http://www.encyclo.co.uk/webster/N/37
   
   
2. 
   Novennial
   • (a.) Done or recurring every ninth year. • (a.) Done or recurring every ninth year.
   Found op http://thinkexist.com/dictionary/meaning/novennial/
   
   
3. 
   novennial
   novennial Done or recurring every ninth year.
   Found op http://www.wordinfo.info/words/index/info/view_unit/1417/
   
   

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