A century is a period of one hundred years. When historians talk about “the 20th century,” they mean the years from 1901 to 2000. The 21st century, which we're living in now, started in 2001 and will end in 2100.

The word comes from the Latin centum, meaning one hundred, which is why you see “cent” in other hundred-related words: a cent is one-hundredth of a dollar, a centipede appears to have a hundred legs, and percent literally means “per hundred.”

Centuries help us organize history into manageable chunks. Instead of saying “the years between 1801 and 1900,” historians simply say “the 19th century.” This makes it easier to discuss big changes over time, like how transportation evolved from horses to railroads during one century, then from early automobiles to jets during the next.

One tricky thing: the 1900s are called the 20th century, not the 19th. That's because the first century AD included years 1 through 100, so each century number is actually one ahead of the year numbers it contains.

In cricket, a century also means scoring one hundred runs in a single innings, which is a major achievement that players celebrate.