Source : Webster's Revised Unabridged Dictionary (1913)

Decennium \De*cen"ni*um\, n.; pl. {Decenniums}, L. {Decennia}.
   [L.]
   A period of ten years. ``The present decennium.'' --Hallam.
   ``The last decennium of Chaucer's life.'' --A. W. Ward.