Definitions
1.NounA group, set, or series of ten .mw-parser-output .defdate{font-size:smaller}, particularly:"a decade of soldiers; The 1960s was a turbulent decade.; I haven’t seen my cousin in over a decade!"
2.NounA period of ten years , particularly such a period beginning with a year ending in 0 and ending with a year ending in 9."The 1960s was a turbulent decade.; I haven’t seen my cousin in over a decade!"
3.NounA period of ten days, particularly those in the ancient Egyptian, Coptic, and French Revolutionary calendars.
4.NounA work in ten parts or books, particularly such divisions of Livy's History of Rome.
5.NounA series of prayers counted on a rosary, typically consisting of an Our Father, followed by ten Hail Marys, and concluding with a Glory Be and sometimes the Fatima Prayer.
6.NounAny of the sets of ten sequential braille characters with predictable patterns.
7.NounA set of ten electronic devices used to represent digits.
8.NounA set of resistors, capacitors, etc. connected so as to provide even increments between one and ten times a base electrical resistance.
9.NounThe interval between any two quantities having a ratio of 10 to 1."There are decades between 1.8 and 18, between 25 and 250 and between 0.03 and 0.003."