For other uses see Decade (disambiguation).

A decade is a period of 10 years. The word is derived (via French) from the Ancient Greek dekas which means ten. This etymology is sometime confused with the Latin decas (ten) and dies (days) which is not correct.1 The other words for spans of years come from Latin: lustrum (5 years) century (100 years) millennium (1000 years). Contents 1 Distinctions 2 See also 3 References 4 External links Distinctions

Although any period of 10 years is a decade23 a convenient and frequently referenced interval is based on the tens digit of the calendar year as in using "1960s" to represent the decade from 1960 to 1969.45 Often for brevity only the tens part is mentioned (60s or sixties) although this may leave it uncertain which century is meant. These references are frequently used to encapsulate popular culture or other widespread phenomena that dominated such a decade as in The Great Depression of the 1930s.

Since the common calendar starts from the year 1 its first full decade contained the years from 1 to 10 the second decade from 11 to 20 and so on.6 So while the "1960s" comprises the years 1960 to 1969 the "197th decade" spans 1961 to 1970.

A decade may also refer to an arbitrary span of 10 years. For example the statement "during his last decade Mozart explored chromatic harmony to a degree rare at the time" merely refers to the last 10 years of Mozart's life without regard to which calendar years are encompassed.

Thus an unqualified reference to for example "the decade" or "this decade" may have multiple interpretations depending on the context. See also List of decades Century Millennium References Larousse etymology of decade(French) Oxford dictionary definition of "decade" Webster dictionary definition of "decade" The OWL at Purdue: Apostrophe WordNet: 1960s Passim i.a. Spencer Donald D. 1989. Invitation to number theory with Pascal. Ormond Beach: Camelot. 46: "The first decade is from 1 to 10 inclusive the second decade from 11 to 20 inclusive and so on." External links Definition from Etymology Online v d eTime measurement and standards Major subjects Time  Chronometry  Orders of magnitude  Metrology International standards UTC  UTC offset  UT  DUT1  IERS  ISO 31-1  ISO 8601  TAI  12-hour clock  24-hour clock  Barycentric Coordinate Time  Civil time  Daylight saving time  Geocentric Coordinate Time  International Date Line  Leap second  Solar time  Terrestrial Time  Time zone Obsolete standards Barycentric Dynamical Time  Ephemeris time  Greenwich Mean Time  Prime Meridian Time in physics Absolute time and space  Spacetime  Chronon  Continuous time  Coordinate time  Cosmological decade  Discrete time  Planck epoch  Planck time  Proper time  Theory of relativity  Time dilation  Gravitational time dilation  Time domain  T-symmetry Horology Clock  Astrarium  Atomic clock  Complication  Equation of time  History of timekeeping devices  Hourglass  Marine chronometer  Marine sandglass  Radio clock  Sundial  Watch  Water clock Calendar Astronomical  Calculating the day of the week  Dominical letter  Epact  Equinox  Gregorian  Intercalation  Islamic  Julian  Leap year  Lunar  Lunisolar  Seven-day week  Solar  Solstice  Tropical year  Week-day names Archaeology & geology Dating methodologies  Geologic time scale  International Commission on Stratigraphy Astronomical chronology Galactic year  Nuclear time scale  Precession  Sidereal time Units of time Century  Day  Decade  Fortnight  Hour  Jiffy  Lustrum  Millennium  Minute  Month  Saeculum  Second  Shake  Tide  Week  Year Related topics Chronology  Duration  Mental chronometry  Metric time  System time  Time value of money  Timekeeper This standards- or measurement-related article is a stub. You can help Wikipedia by expanding it.v d e