- a group of ten
- a period of ten years; esp., in the Gregorian calendar
- officially a ten-year period beginning with the year 1, as 1921-1930, 1931-1940, etc.
- in common usage, a ten-year period beginning with a year 0, as 1920-1929, 1930-1939, etc.
- a division of the rosary consisting of one large bead and ten small beads
Origin of decadeLate Middle English from Old French from Late Latin decas (gen. decadis) from Classical Greek dekas from deka, ten