decade

Etymology

From Middle English decade, from Old French decade, from Late Latin decādem (“(set of) ten”), from Ancient Greek δεκάς (dekás), from δέκα (déka, “ten”). In reference to a span of ten years, originally a clipping of the phrase decade of years. Synchronically, deca- + -ade.

noun

1. A group, set, or series of ten
   1. A 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!
      Thru May: 1920s — The Decade That Roared. New exhibition portraying historical events and everyday life during the Roaring Twenties. 1979 December, “Museums”, in Texas Monthly, volume 7, number 12, page 22
      Athletes' use of herbal supplements has skyrocketed in the past two decades. 2013 March, David S. Senchina, “Athletics and Herbal Supplements”, in American Scientist, volume 101, number 2, archived from the original on 2013-05-16, page 134
      Some of these employees have been with the company for decades, which made the company's claims that it offers good training, positive management and excellent job security and benefit packages all the more compelling. January 2 2020, Paul Stephen, “A great place to work”, in Rail, page 29
   2. A period of ten days, (history) particularly those in the ancient Egyptian, Coptic, and French Revolutionary calendars.
      The year was divided up into twelve months renamed after the seasons …; each month comprised three ‘decades’ of ten days – with the décadi replacing Sundays as a day of rest; and each day was reconsecrated to a natural product or farming tool or technique. 2002, Colin Jones, The Great Nation, Penguin, published 2003, page 481
   3. (literary, archaic) A work in ten parts or books, particularly such divisions of Livy's History of Rome.
   4. (Roman Catholicism) A 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.
   5. Any of the sets of ten sequential braille characters with predictable patterns.
   6. (electronics) A set of ten electronic devices used to represent digits.
2. (electronics) A set of resistors, capacitors, etc. connected so as to provide even increments between one and ten times a base electrical resistance.
3. (physics, engineering) The 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.