Main Entry: de·cen·ni·al

Pronunciation: \di-ˈse-nē-əl\

Function: adjective

Date: circa 1656

1 : consisting of or lasting for 10 years
2 : occurring or being done every 10 years <the decennial census>

— decennial noun

— de·cen·ni·al·ly \-nē-ə-lē\ adverb