[dek-eyd; Brit. also duh-keyd] 
| 1. | a period of ten years: the three decades from 1776 to 1806. |
| 2. | a period of ten years beginning with a year whose last digit is zero: the decade of the 1980s. |
| 3. | a group, set, or series of ten. |
| dec·ade (děk'ād', dě-kād') n.
[Middle English, a group of ten, from Old French, from Late Latin decas, decad-, from Greek dekas, from deka, ten; see dek  in Indo-European roots.] |
eɪd