A century is a period of 100 years. It is commonly used to measure time in history, culture, and events. For example, the 20th century refers to the years from 1901 to 2000. Centuries are often divided into decades, which are ten-year periods, making it easier to discuss trends and changes over time.
In the Gregorian calendar, which is widely used today, centuries are numbered sequentially. The first century includes the years 1 to 100, while the second century spans from 101 to 200. Significant events, such as the Industrial Revolution or the American Civil War, are often categorized by the century in which they occurred.