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July 30, 2026Short & citedBlog
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Everyday Life • History

Centuries

A century is a period of 100 years.

Updated July 30, 20261 min readCited sources

A century is a period of 100 years. In historical dating, centuries are numbered ordinally from the start of the Common Era.

What it is

A century is a unit of time equal to 100 years. The word can also refer to any group of 100 items, but its main historical meaning is a 100-year period. In calendar history, centuries are numbered as ordinals: 1st, 2nd, 3rd, and so on.

How centuries are numbered

In the Common Era system, the 1st century covers years 1–100, the 2nd covers 101–200, and the pattern continues. For example, the 19th century ran from 1801 to 1900, and the 21st century began in 2001 and will end in 2100.

Why it matters

Historians use centuries to organize events, trends, and periods of change, such as industrialization in the 19th century or digital technology in the 21st. Canadian history is often organized by centuries, with the 19th century including Confederation in 1867 and the early development of modern Canada.

In short

  • A century equals 100 years.
  • Centuries are numbered ordinally (1st, 2nd, 3rd…).
  • The 21st century began in 2001.
  • Canadian history is often grouped by centuries.
Canadian angle

Canadian history is often organized by centuries, especially the 19th century, which included Confederation in 1867 and the early development of modern Canada.

Quick questions

What is the definition of a century?
A century is a period of 100 years.
How many years are in a century?
There are 100 years in a century.
What is the 21st century known for?
The 21st century is commonly associated with rapid digital technology, globalization, social media, and major climate and public-health challenges.

Sources

  1. Merriam-Websterhttps://www.merriam-webster.com/dictionary/century
    Supports: Definition of century as a period of 100 years and as one of the 100-year divisions of history.
  2. Cambridge Dictionaryhttps://dictionary.cambridge.org/us/dictionary/english/century
    Supports: Definition of century as a period of 100 years and historical use in dating.
  3. Collins Dictionaryhttps://www.collinsdictionary.com/us/dictionary/english/century
    Supports: Century as a 100-year period and examples of calendar-century ranges.
  4. Math Is Funhttps://www.mathsisfun.com/definitions/century.html
    Supports: Century numbering examples, including 1st century 1–100 and 21st century 2001–2100.
  5. Britannica Dictionaryhttps://www.britannica.com/dictionary/century
    Supports: Century defined as a period of 100 years, including historical dating usage.