Century (noun)

1. A period of 100 years, especially one beginning with a year ending in 00.
2. A group or set of 100 similar things.

Origin:

From middle english century, from old french century, from latin centuria ("a group of one hundred"), from centum ("one hundred") + -ia.

Examples:

1. The 21st century began on January 1, 2001.
2. The novel is set in the 19th century.
3. A century of progress has been made in medicine.
4. The city was founded in the 18th century.
5. The company has been in business for over a century.