WordReference Random House Unabridged Dictionary of American English © 2026
de•cen•ni•um
(di sen′ē əm),USA pronunciation n., pl. -cen•ni•ums, -cen•ni•a
-
(-sen′ē ə).USA pronunciation
- a period of ten years;
a decade.
- Latin; see decennial
- 1675–85
'decennium' also found in these entries (note: many are not synonyms or translations):