Blog about English
Reading, writing and referring to years, decades and centuries.
Years identify specific calendar years, decades identify periods of ten years, and centuries identify periods of one hundred years.
For example, 2026 is a year, the 2020s is a decade, and the twenty-first century is a century.
Four-digit years are commonly pronounced as two pairs of digits when the structure allows it.
For example, 1984 is commonly nineteen eighty-four and 2026 is commonly twenty twenty-six.
Years from 2000 through 2009 are commonly pronounced using two thousand followed by the remaining number, although other patterns can occur.
For example, 2005 is commonly two thousand and five or two thousand five.
Years after 2010 can be read using twenty followed by the final two digits, especially in contemporary speech.
For example, 2016 is commonly twenty sixteen and 2026 is twenty twenty-six.
The year 2000 is normally pronounced two thousand rather than twenty hundred in ordinary modern English.
For example, The company was founded in two thousand.
Historical years can be identified using BC before the common era and AD for years traditionally described as Anno Domini.
For example, 44 BC and AD 476.
BCE and CE provide non-religious terminology corresponding approximately to BC and AD.
For example, 44 BCE and 476 CE.
The conventional BC/AD and BCE/CE calendar systems do not contain a year zero.
The sequence goes from 1 BCE to 1 CE.
In is normally used before a year when identifying when something happened.
For example, She was born in 1990 and The company started in 2020.
Since introduces a year as the starting point of a continuing situation.
For example, I have lived here since 2020.
By identifies a deadline or point no later than a specified year.
For example, The project must be completed by 2030.
From ... to expresses a span between two years.
For example, The study covered the period from 2010 to 2020.
A decade is commonly written with a pluralized decade number ending in -s.
For example, the 1980s refers to the years 1980 through 1989.
The 2020s refers to the ten-year period from 2020 through 2029.
For example, technology changed rapidly during the 2020s.
Informal writing may abbreviate a decade by omitting the first two digits, commonly using an apostrophe before the remaining digits.
For example, the '80s means the 1980s or another decade depending on context.
Decade names normally take a plural -s without an apostrophe when the digits are fully written.
For example, the 1990s and the 2020s, not the 1990's or 2020's.
Early and late can identify approximate portions of a decade.
For example, the early 1990s, the mid-1990s, and the late 1990s.
Mid can combine with a decade name to refer approximately to the middle part of that decade.
For example, The company expanded in the mid-1980s.
Decade is a singular countable noun referring to a period of ten years.
For example, over the past decade and during the next decade.
A decade ago refers to a period of approximately ten years before the present or another reference point.
For example, We first met a decade ago.
The phrase the first decade can refer to different ten-year periods depending on the historical or numerical reference system, so context should clarify the intended interval.
For example, the first decade of the twenty-first century conventionally refers to 2001–2010.
Centuries are conventionally named with ordinal numbers rather than cardinal numbers.
For example, the twentieth century and the twenty-first century.
The first century covers years 1–100, the second covers 101–200, and each later century follows the same pattern.
For example, the twentieth century covers 1901–2000 and the twenty-first covers 2001–2100.
The number naming a century is one greater than the first two digits of most years within it.
For example, 1900 is in the nineteenth century, while 1901 begins the twentieth century.
The 1900s commonly refers to 1900–1909, while the twentieth century covers 1901–2000.
These expressions are related but are not interchangeable.
The 2000s commonly refers to 2000–2009, while the twenty-first century begins in 2001.
These expressions overlap in everyday usage but represent different numerical intervals.
A century can be divided into its first and second halves to describe broad historical periods.
For example, the first half of the twentieth century and the second half of the nineteenth century.
Early and late can describe approximate periods within a century.
For example, the early twentieth century and the late nineteenth century.
The turn of the century refers approximately to the period when one century changes to another.
For example, around the turn of the twentieth century.
A millennium is a period of one thousand years.
For example, the third millennium began in 2001 under conventional Gregorian calendar numbering.
Millennia are conventionally numbered in the same way as centuries, with the first millennium covering years 1–1000.
For example, the second millennium covers 1001–2000.
Historical periods can be expressed using individual years, decades, centuries, or larger periods depending on the precision required.
For example, in 1066, during the eleventh century, or in the medieval period.
Approximate years can be introduced with around, about, approximately, or by other context-dependent expressions.
For example, around 1900, about 500 BCE, and approximately 2,000 years ago.
Year ranges can be written with from ... to, between ... and, a hyphen, or an en dash depending on context.
For example, from 2010 to 2020 and 2010–2020.
Use correct year pronunciation, decade pluralization, century numbering, and prepositions when referring to historical periods.
Common mistakes include writing 1990's instead of 1990s, confusing the twentieth century with the 1900s, saying in the twenty-first century for a specific year without the correct preposition, and misidentifying century boundaries.