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 decade,23 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